A SUBSTRATE FOR FORMATION OF A POLYMER BRUSH, A PROCESS OF PRODUCING THE SUBSTRATE, AND A PRECURSOR SOLUTION USED WITH THE PROCESS

Abstract

The present invention provides a surface treatment technology that gives excellent surface functionality to surfaces of a variety of large-area substrate materials. According to the present invention, when precursor solution containing an organosilane and a metal alkoxide is coated on a substrate material to form a polymerization initiator layer by a sol-gel process, a polymerization initiator group-containing organosilane having a formula: XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n (X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3) is used as the organosilane.

Claims

1. A substrate for formation of a polymer brush, comprising a substrate material, and a polymerization initiator layer formed on a surface of said substrate material, wherein said polymerization initiator layer contains a hydrolysate/condensation polymer of an organosilane and a metal alkoxide, wherein said organo-silane is a polymerization initiator group-containing organosilane having the following formula (1):
XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I) where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

2. The substrate for formation of the polymer brush according to claim 1, wherein said organosilane further contains a second organosilane having the following formula (II):
R.sup.5-(Ph).sub.p-(R.sup.6).sub.qSiR.sup.7.sub.rR.sup.8.sub.3-r(II) where R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Ph stands for a phenylene group, R.sup.6 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.7 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.8 stands for an alkyl group having 1 to 6 carbon atoms, p is 0 or 1, q is 0 or 1, and r is 1, 2 or 3.

3. The substrate for formation of the polymer brush according to claim 1, wherein said polymerization initiator layer has a thickness of 10 to 20000 nm.

4. The substrate for formation of the polymer brush according to claim 1, wherein said substrate material is formed of a resin.

5. The substrate for formation of the polymer brush to claim 4, wherein said resin is at least one selected from the group consisting of a polyethylene terephthalate resin, a polycarbonate resin, an acrylic resin, a silicone resin, and an ABS resin.

6. A precursor solution for producing the substrate for formation of the polymer brush according to claim 1, wherein by containing an organic solvent, water, a sol-gel catalyst, a metal alkoxide, and a polymerization initiator group-containing organosilane, wherein said organosilane has the following formula (I):
XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I) where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

7. The precursor solution according to claim 6, wherein by further containing a second organosilane having the following formula (II):
R.sup.5-(Ph).sub.p-(R.sup.6).sub.qSiR.sup.7.sub.rR.sup.8.sub.3-r(II) where R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Ph stands for a phenylene group, R.sup.6 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.7 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.8 stands for an alkyl group having 1 to 6 carbon atoms, p is 0 or 1, q is 0 or 1, and r is 1, 2 or 3.

8. A substrate material, which is provided with the polymer brush in which monomers are polymerized with said polymerization initiator groups of the substrate for formation of the polymer brush according to claim 1 as starting points.

9. The substrate material provided with the polymer brush according to claim 8, wherein plating layers are formed on a surface of said substrate material.

10. A process of producing a substrate for formation of a polymer brush, wherein a precursor solution comprising an organic solvent, water, a sol-gel catalyst, a metal alkoxide, and a polymerization initiator group-containing organosilane is coated onto a substrate material, and a polymerization initiator layer is formed by a sol-gel process on said substrate material, wherein said organosilane has the following formula (I):
XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I) where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

11. The process of producing the substrate for formation of the polymer brush according to claim 10, wherein said precursor solution further contains a second organosilane having the following formula (II):
R.sup.5-(Ph).sub.p-(R.sup.6).sub.qSiR.sup.7.sub.rR.sup.8.sub.3-r(II) where R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Ph stands for a phenylene group, R.sup.6 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.7 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.8 stands for an alkyl group having 1 to 6 carbon atoms, p is 0 or 1, q is 0 or 1, and r is 1, 2 or 3.

12. A process of producing a polymer brush comprising: a step of coating a precursor solution comprising an organic solvent, water, a sol-gel catalyst, a metal alkoxide, and a polymerization initiator group-containing organosilane on a substrate material, and forming a polymerization initiator layer having a thickness of 10 to 20000 nm by a sol-gel process on said substrate material thereby obtaining a substrate for formation of a polymer brush, and a polymer brush growth step of polymerizing a monomer with the polymerization initiator group of said substrate for formation of a polymer brush as starting points for growth of the polymer brush, wherein said organosilane has the following formula (I):
XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I) where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

13. The process of producing the polymer brush according to claim 12, wherein said precursor solution further contains a second organosilane having the following formula (II):
R.sup.5-(Ph).sub.p-(R.sup.6).sub.qSiR.sup.7.sub.rR.sup.8.sub.3-r(II) where R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Ph stands for a phenylene group, R.sup.6 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.7 stands for an alkoxy chloro group having 1 to 3 carbon atoms, R.sup.8 stands for an alkyl group having 1 to 6 carbon atoms, p is 0 or 1, q is 0 or 1, and r is 1, 2 or 3.

14. A process of forming a plating layer on a polymer brush side surface of the substrate material, wherein after forming the polymer brush by the process according to claim 12 on the surface of the substrate material, a plating catalyst is fixed to the polymer brush formed on said substrate material, followed by application of electroless plating.

Description

MODES FOR CARRYING OUT THE INVENTION

[0028] The present invention relates to a substrate for formation of a polymer brush wherein a solid surface is provided with a polymerization initiator layer containing the polymerization initiator group necessary for formation of the polymer brush, characterized in that said polymerization initiator layer is obtained by the co-hydrolysis and condensation polymerization of an organosilane and a metal alkoxide in a solution containing or comprising an organic solvent, water, and a sol-gel catalyst, and said organosilane contains a polymerization initiator group-containing organosilane having the following formula (I):

XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I)

where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

[0029] In the substrate for formation of the polymer brush according to the invention, polymer chains are extended by the SI-ATRP process from the surface of the polymerization initiator layer, resulting in the formation of the polymer brush.

[0030] The present invention is also concerned with a process of forming a polymerization initiator layer containing the polymerization initiator group necessary for formation of a polymer brush on a surface of a substrate material as well as a precursor solution used with said process, characterized in that a precursor solution obtained by co-hydrolysis and condensation polymerization of said polymerization initiator group-containing organosilane and metal alkoxide in a solution comprising an organic solvent, water and a sol-gel catalyst, and leaving the substrate material at rest for a given time at room temperature under atmospheric pressure for volatilization of the solvent and crosslinking. It is here noted that heating may also be applied so as to make the drying time of the coated film short.

[0031] Further, the present invention relates to a polymer brush polymerized by the SI-ATRP process from the surface of the aforesaid polymerization initiator layer, characterized in that the polymer brush is obtained by dipping the aforesaid polymerization initiator layer in a solution containing a monomer, water and an organic solvent optionally with a metal salt, a ligand, a reducing agent, etc., leaving the initiator layer at rest for a given time at room temperature under atmospheric pressure, and washing a surface thereof, and that the obtained surface shows water/oil repellency, slippage capability, droplet removal capability, fingerprint resistance, antifogging capability, slidability, corrosion resistance, antibacterial activity, etc.

[0032] Furthermore, the present invention relates to a process of forming a polymer brush by polymerization from the surface of the aforesaid polymerization initiator layer by the SI-ATRP process, characterized in that the aforesaid polymerization initiator layer is dipped in a solution containing a monomer, water and an organic solvent optionally with a metal salt, a ligand, a reducing agent, etc., and left at rest for a given time at room temperature under atmospheric pressure, and washed on the surface.

[0033] The present invention as described above ensures that the polymer brush having enhanced adherence is formed on a variety of large-area substrate materials thereby giving the surface of the substrate material a variety of functions such as water/oil repellency, super-hydrophilicity, slippage capability, droplet removal capability, fingerprint resistance, antifogging capability, slidability, corrosion resistance, antibacterial activity and capability of carrying a plating catalyst.

[0034] In the invention, the metal alkoxide and the polymerization initiator group-containing organosilane are mixed together in a (metal alkoxide/organosilane) molar ratio of 4 or higher, preferably 5 to 400, and most preferably 10 to 80, the obtained polymer initiator layer is capable of adhering firmly to a substrate material selected from the group consisting of a metal, a metal oxide film, an alloy, a semiconductor, a polymer, ceramics, a glass, a resin, wood, a fiber and paper; and the polymerization initiator layer is capable of adhering firmly to a hybrid surface comprising at least one selected from the group consisting of a plane, a curved surface, an uneven or irregular surface and a porous surface. It is here to be noted that when a numerical range or the like is expressed in terms of - to -, it will include the numerals of both its ends.

[0035] In one preferred embodiment of the invention, the molar ratio between the polymerization initiator group-containing and the metal alkoxide is regulated such that when the substrate material is dipped in the polymerization solution, solvent cracks and film peeling are prevented or held back, resulting in the formation of a uniform or even polymer brush.

[0036] The present invention will now specifically be described with reference to some embodiments inclusive of its best mode.

Substrate Materials

[0037] The substrate materials usable here include any desired materials such as metals, metal oxide films, alloys, semiconductors, polymers, ceramics, glasses, resins, woods, papers, and fibers. Specific examples of the substrate material preferably include copper, brass, silicon, polyethylene terephthalate resins, polycarbonate resins, acrylic resins, silicone resins, ABS resins, glasses and woods, among which resins such as polyethylene terephthalate resins, polycarbonate resins, acrylic resins, silicone resins, and ABS resins are used.

[0038] The substrate materials may have any desired shape such as a sheet shape, an uneven shape, a powdery shape, a tubular shape, a porous shape, and a fibrous shape.

[0039] Any particular pretreatment may not be needed in the invention, but any substrate material may be used after pretreated as by washing/activation with plasmas or UV.

[0040] Alternatively, any substrate material may be used after provided with any easy-to-bond layer.

Polymerization Initiator Group-Containing Polymerization Initiator Layer

[0041] The polymerization initiator group-containing polymerization initiator layer according to the invention is obtained by co-hydrolysis and condensation polymerization of the polymerization initiator group-containing organosilane and metal alkoxide in a solution comprising an organic solvent, water and a sol-gel catalyst with a thickness of preferably 10 to 20000 nm, more preferably 100 to 1000 nm, and most preferably 250 to 700 nm.

Polymerization Initiator Group-Containing Organosilane

[0042] Usually, an organohalogenide having a highly reactive carbon-halogen bond is used for the polymerization initiator in the SI-ATRP process.

[0043] The polymerization initiator group-containing organosilane according to the invention, too, is an organohalogen compound having a highly reactive carbon-halogen bond and represented by the following formula (I):

XR.sup.1-(Ph).sub.k-(R.sup.2).sub.mSiR.sup.3.sub.nR.sup.4.sub.3-n(I)

where X stands for a halogen atom, R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms, Ph stands for a phenylene group, R.sup.2 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.3 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.4 stands for an alkyl group having 1 to 6 carbon atoms, k is 0 or 1, m is 0 or 1, and n is 1, 2 or 3.

[0044] That is, the organosilane of the invention represented by Formula (1) is characterized by including an XR.sup.1-(Ph).sub.k-(R.sup.2).sub.m group as the polymerization initiator group and an R.sup.3 group as a functional group with no easy-to-hydrolyze functional group between XR.sup.1 functioning as the polymerization initiator group and Si.

[0045] In Formula (I), X stands for a halogen atom preferably selected from chlorine (Cl), bromine (Br) or iodine (I), and R.sup.1 stands for an alkylene group having 1 to 3 carbon atoms that may have a branch.

[0046] A specific XR.sup.1 group is exemplified as by

##STR00001##

where X stands for chlorine, bromine or iodine. More preferably, there is the mention of a chloromethyl group, 2-chloropropyl group, and 2-bromopropyl group.

[0047] There may be a phenylene group present between the XR.sup.1 group and Si, and XR.sup.1-Ph- may be a chloromethylphenyl group or a bromomethylphenyl group as an example.

[0048] Further between the aforesaid XR.sup.1 and Si or between the aforesaid XR.sup.1-Ph- and Si, there may be a C1 to C10 alkylene group represented by R.sup.2, optionally via an oxygen atom. For instance, one example of XR.sup.1-Ph-R.sup.2 is a chloromethylphenylethyl group or the like.

[0049] The number (n) of R.sup.3 in the aforesaid polymerization initiator group-containing organosilane is 1, 2 or 3, and an alkoxy or chloro group may be selected as R.sup.3. A preferable example of the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group or an isopropoxy group. For the chloro group-containing silane, hydrochloric acid produced after hydrolysis may be used as a catalyst for the sol-gel reaction.

[0050] R.sup.4 in the aforesaid organosilane containing polymerization initiator group stands for an alkyl group having 1 to 6 carbon atoms, and its number (3n) is 2, 1 or 0 as determined depending on the number (n) of R.sup.3.

[0051] Specific examples of the polymerization initiator group-containing organosilane include compounds having the following formulae.

##STR00002##

where X=chlorine or bromine, and R.sup.3=chlorine or methoxy group (R.sup.3=methoxy or ethoxy group). More preferably, there is the mention of (chloromethyl)phenylethyl-trichlorosilane, (chloromethyl)phenylethyltrimethoxysilane, (chloromethyl)phenyltrichlorosilane, (chloromethyl)phenyl-trimethoxysilane, (bromomethyl)-pentyltrimethoxysilane, triethoxy(bromomethylpentyl)-silane, (chloromethyl)pentyl-trimethoxysilane, and triethoxy(chloromethylpentyl)-silane.

Second Silane

[0052] The organosilane in the hydrolysate/condensation polymer of the aforesaid organosilane and metal alkoxide may include, in addition to the polymerization initiator group-containing organosilane having the aforesaid formula (I), the second organosilane having the following formula (II):

R.sup.5-(Ph).sub.p-(R.sup.6).sub.qSiR.sup.7.sub.rR.sup.8.sub.3-r(II)

where R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Ph stands for a phenylene group, R.sup.6 stands for a C1 to C10 alkylene group optionally via an oxygen atom, R.sup.7 stands for an alkoxy or chloro group having 1 to 3 carbon atoms, R.sup.8 stands for an alkyl group having 1 to 6 carbon atoms, p is 0 or 1, q is 0 or 1, and r is 1, 2 or 3.

[0053] The second organosilane having the aforesaid formula (II) is an organosilane free from any polymerization initiator group, wherein R.sup.5 is positioned in place of XR.sup.1 functioning as the polymerization initiator group in the aforesaid formula (I). R.sup.5 stands for a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, wherein said alkyl group may have a branch.

[0054] Between the aforesaid R.sup.5 and Si there may be a phenylene group (-Ph-) present, and an example of R.sup.5-Ph- may include a phenyl group, a methylphenyl group, an ethylphenyl group or the like.

[0055] Further, between the aforesaid R.sup.5 and Si or between the aforesaid R.sup.5-Ph- and Si, there may be a C1 to C10 alkylene group optionally via an oxygen atom, and one example of R.sup.5-Ph-R.sup.6 may include a methylphenylethyl group or the like.

[0056] The number (r) of R.sup.7 in the aforesaid second organo-silane is 1, 2 or 3, and an alkoxy group or a chloro group may be selected as R.sup.7. A preferable example of the alkoxy group is a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group or the like. For the silane having a chloro group, hydrochloric acid produced after hydrolysis may be used as a catalyst for the sol-gel reaction.

[0057] R.sup.8 in the aforesaid second organosilane is an alkyl group having 1 to 6 carbon atoms, and its number (3r) is 2, 1 or 0 as determined depending on the number (r) of R.sup.7.

[0058] Specifically, the second organosilane represented by the aforesaid formula (II) includes analogs of the organosilane recited in [0037] out of which the halogen atom is excluded; more preferably, it includes phenyltriethoxysilane, phenyltrimethoxysilane, phenylpropyl-triethoxysilane, phenylpropyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane or the like.

[0059] The use of a mixture of the second organosilane having the aforesaid formula (II) with the polymerization initiator group-containing organosilane having the aforesaid formula (I) allows for control of the polymerization initiation point.

[0060] The second organosilane may be mixed with the polymerization initiator group-containing organosilane represented by the aforesaid formula (I) in a ratio of 1% by volume to 10000% by volume, and preferably 10% by volume to 100% by volume.

Metal Alkoxide

[0061] The metal alkoxide usable here includes, but is not limited to, those known so far in the art. For instance, there is the mention of a metal alkoxide in which a molecule containing at least two alkoxy groups or tetraalkoxysilane has an oligomeric configuration with a metal atom as center, or the following compounds having an effect equal or similar thereto.

[0062] That is, the metal alkoxide is exemplified by tetra-methoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-t-butoxysilane, triethoxyaluminum, tri-n-propoxyaluminum, tri-i-propoxyaluminum, tri-n-butoxyaluminum, tri-t-butoxyaluminum, dimethoxycalcium, diethoxycalcium, di-i-propoxycalcium, di-n-butoxycalcium, triethoxyiron, tetra-methoxygermanium, tetraethoxygermanium, tetra-i-propoxy-germanium, tetra-n-butoxygermanium, tetra-t-butoxygermanium, tetramethoxyhafnium, tetraethoxyhafnium, tetra-i-propoxyhafnium, tetra-n-butoxyhafnium, tetra-t-butoxyhafnium, trimethoxyindium, triethoxyindium, tri-i-propoxyindium, tri-n-butoxyindium, tri-t-butoxyindium, pentamethoxytantalum, pentaethoxytantalum, penta-i-propoxytantalum, penta-t-butoxytantalum, penta-n-butoxytantalum, tetramethoxytitanium, tetraethoxy-titanium, tetra-i-propoxytitanium, tetra-n-butoxytitanium, tetra-t-butoxytitanium, tetramethoxytin, tetra-ethoxytin, tetra-i-propoxytin, tetra-n-butoxytin, tetra-t-butoxytin, polydialkoxysilane or the like.

[0063] A preferable metal alkoxide in particular is exemplified by a compound represented by Si(OR.sup.5).sub.4 where R.sup.5 stands for a lower alkyl group such as a methyl group, an ethyl group, and a propyl group.

Organic Solvent

[0064] Using a precursor solution comprising an organic solvent, water, a sol-gel catalyst, a metal alkoxide and a polymerization initiator group-containing organosilane optionally with a second organosilane (the polymerization initiator group-containing organosilane and the second organosilane will sometimes be collectively called the organosilane), the polymerization initiator group-containing polymerization initiator layer according to the invention is formed by the sol-gel process on the aforesaid substrate material.

[0065] To form a transparent, uniform coating film according to the invention, it is desired that the organic solvent used as a part of the precursor solution be miscible with a small amount of water and capable of dissolving a condensation polymer of the organosilane/metal alkoxide, and that it evaporate off as soon as the precursor solution is coated onto the substrate material. In other words, it is herein preferable to use an organic solvent having a vapor pressure higher than that of water for the preparation of the precursor solution.

Water

[0066] Referring here to the amount of water to be added, it is desired that water be contained in an amount exceeding the number of functional groups for the purpose of allowing all reactive functional groups contained in the precursor solution to be hydrolyzed to form the M-OH groups. While a coating film may somewhat be formed even in an amount of water less than the aforesaid number, yet it is not preferred because, thanks to insufficient hydrolysis, an unhydrolyzed portion of the organosilane and metal alkoxide vaporizes off during treatment, resulting in poor yields.

[0067] If the above-exemplified organic solvent is used to adjust the concentration of the organosilane and metal alkoxide, it is then possible to control film thickness within the range of 10 to 20000 nm, because when a certain amount of the precursor solution is added dropwise onto the surface of the substrate material to form a coating film incidental to the volatilization of the solvent, the higher the concentration of the organosilane and metal alkoxide or solid components contained in the precursor solution, the more solid is precipitated on the surface of the substrate material.

[0068] It is noted that the organosilane has a surface energy lower than that of the M-OH group generated from the metal alkoxide in the process of condensation polymerization, meaning that the organosilane is likely to remain concentrated on the surface of the polymerization initiator layer in the process of forming the polymerization initiator layer.

[0069] It follows that the surface concentration of the organosilane grows higher than its bulk (organosilane/metal alkoxide composition ratio).

Sol-Gel Catalyst

[0070] It is desired for the precursor solution to make use of a catalyst for accelerating hydrolysis of the reactive functional groups of the organosilane and metal alkoxide (to form the M-OH group); a catalyst effective for acceleration of hydrolysis of the alkoxy group is used as said sol-gel catalyst.

[0071] It is desired to control the pH of said precursor solution by the catalyst thereby stabilizing the organo-silane/metal alkoxide condensation polymer. For instance, when the organosilane contains an alkoxysilyl group, it is then preferable to use an organic acid such as hydrochloric acid, and p-toluenesulfonic acid thereby controlling the pH to 1 to 3.

[0072] When the organosilane contains a chlorosilyl group, hydrochloric acid generated as a by-product of said organosilane after hydrolysis may be used as the catalyst for the sol-gel reaction without recourse to any particular catalyst.

How to Form the Polymerization Initiator Layer

[0073] To form the polymerization initiator layer according to the invention, the precursor solution comprising an organic solvent, water, a sol-gel catalyst, a metal alkoxide and a polymerization initiator group-containing organosilane optionally with a second organosilane is coated onto a substrate material, and formed by the sol-gel process on said substrate material.

[0074] There is no particular limitation on how to coat the precursor solution provided that the volatilization of the solvent is accelerated; for instance, any one selected from the group consisting of spin coating, dip coating, roller coating, bar coating, ink jet coating, gravure coating, and spraying is available.

[0075] It is preferred that by accelerating the volatilization of the solvent after the coating of the precursor solution, the concentration of the organosilane and metal alkoxide in the precursor solution is regulated to control a post-drying thickness of the polymerization initiator layer within a range of 10 to 20000 nm.

[0076] While there is no particular limitation on the drying temperature of the polymerization initiator layer with the proviso that the solvent used can be volatilized off, the drying temperature is preferably 0 to 150 C., and more preferably room temperature to 100 C.

[0077] The drying time of the polymerization initiator layer is preferably 1 minute to 24 hours, although varying with the solvent used and temperature.

[0078] For formation of the polymerization initiator layer, the roll-to-roll type film-making system may also be used due to its good mass productivity.

Formation of the Polymer Brush

[0079] According to the invention, any desired polymerizable monomer having a vinyl group applicable to the SI-ATRP process may be used, while the polymerization initiator layer formed on the substrate for formation of the polymer brush is set as a starting point, to form the polymer brush according to the invention on the surface of a variety of large-area substrate materials. Monomer polymerization conditions may optionally be selected depending on the monomer species used. Polymerization temperature and time may optionally, or not exclusively, be set depending on the polymerization initiator and monomer species used as well as the desired function(s) and polymer brush thickness.

[0080] In the invention, although there is no particular limitation on how to carry out polymerization, it is preferable to use a process of dipping a substrate material having a polymerization initiator layer in a polymerization solution regulated by a monomer, an organic solvent and so on, a process of dropwise adding or direct coating of the polymerization solution onto a substrate material having a polymerization initiator layer formed on it, and so on.

Polymerization Solution for Formation of the Polymer Brush

[0081] In a preferable embodiment of the invention, the polymerization solution provided for formation of the polymer brush contains a monomer, a metal salt for catalysts, a metal ligand, and a reducing agent.

[0082] In an embodiment of the invention, the monomer concentration in the polymerization solution is preferably 1 to 100% by volume, and more preferably 5 to 50% by volume. Depending on the monomer concentration and polymerization time, it is possible to control polymer brush thickness within a range of 1 to 2000 nm.

[0083] The thickness of the polymer brush to be formed is preferably 1 to 2000 nm, and more preferably 1 to 1000 nm.

[0084] In the invention, while there is no particular limitation on the monomer type, it is understood that acrylic acid and its ester (dimethylaminoethyl methacrylate), methacrylic acid and its ester (methyl methacrylate), styrene and its derivative (styrene), and mixtures thereof may be exemplified.

[0085] The polymerization solution may further contain an organic solvent capable of being miscible with the monomer. While there is no particular limitation on the solvent, it is preferable to use an alcohol (methanol, ethanol, and isopropanol), an organic solvent (anisole, dimethylformamide, and acetonitrile), water, or a mixture thereof.

[0086] In the invention, a polymerization solution obtained by mixing an alcohol, water and an organic solvent in any desired ratio may be used depending on the monomer type, wherein said ratio is, but not limited to, preferably 10 to 90% by volume, and more preferably 40 to 60% by volume.

[0087] In the invention, there is no particular limitation on the metal salt for catalysts usable in the aforesaid polymerization solution; those known so far in the art may be used. For instance, use may be made of metal chlorides or bromides comprising copper, iron, cobalt, titanium, molybdenum or ruthenium as a metal element and having any one of monovalent, divalent and trivalent charges. Specifically, there is the mention of copper (I) chloride, copper (II) chloride, copper (I) bromide, copper (II) bromide, titanium (II) chloride, titanium (III) chloride, titanium (IV) chloride, titanium (IV) bromide, iron (II) chloride, iron (III) chloride, iron (II) bromide, iron (III) bromide, cobalt (II) chloride, cobalt (II) bromide, nickel (III) chloride, nickel (II) bromide, molybdenum (III) chloride, molybdenum (V) chloride, ruthenium (III) chloride or the like.

[0088] In the invention, the molar ratio of metal salt for catalysts relative to monomer is preferably 0.004 to 0.03.

[0089] In the invention, there is no particular limitation on the metal ligand usable in the aforesaid polymerization solution; those known so far in the art may be used. For instance, use may be made of metal ligands that form a complex with a metal chloride or bromide and has reactivity in the SI-ATRP process. Specifically, there is the mention of reaction solutions or the like that are 2,2-bipyridyl, 4,4-dimethyl-2,2-bipyridyl, 4,4-di-t-butyl-2,2-bipyridyl, 4,4-dinonyl-2,2-bipyridyl, N,N,N,N,N-pentamethyldiethylenetriamine, tris(2-pyridylmethyl)amine, and ethylene-diamine.

[0090] In the invention, the molar ratio of metal ligand relative to metal salt for catalysts used may vary optionally with the type of metal salt for catalysts and metal ligand used; that molar ratio is preferably 1:1 to 1:3.

[0091] In the invention, the aforesaid polymerization solution may contain a reducing agent capable of reducing the metal in the aforesaid complex.

[0092] By way of example but not by way of limitation, the reducing agent used here includes Cu(O), AIBN, ascorbic acid, sodium ascorbate, tin(II) 2-ethylhexanoate, etc., among which ascorbic acid that has less environmental load and strong reducing action is most preferred.

[0093] In the invention, the reducing agent should preferably be uniformly dissolved in the polymerization solution, but uniform dissolution is not always needed.

[0094] In the invention, the molar ratio of reducing agent relative to metal salt is preferably 1:0.30 to 1:50, and most preferably 1:1. If the molar ratio of reducing agent relative to metal salt for ATRP catalyst is at least 0.30, the reducing agent can then function as a reductant capable of holding back a lowering of the concentration of the metal salt for ATRP catalysts (e.g., copper (I) chloride), and if it is 50 or lower, it is then possible to hold back polymerization termination.

[0095] The present invention has such advantages as mentioned below. [0096] (1) The polymerization initiator layer necessary for the SI-ATRP process may be formed on the surface of a variety of substrate materials in a simple yet uniform way. [0097] (2) By regulation of the concentration of the organo-silane and metal alkoxide relative to the organic solvent, it is possible to gain optional control of the thickness of the polymerization initiator layer within the range of (10 to 20000 nm). [0098] (3) The post-preparation precursor solution, because of remaining stabilized, may be used over an extended period of time. [0099] (4) The aforesaid polymerization initiator layer, because of being no in need of heating treatment and being capable of being cured at room temperature, may be formed even on a polymer, paper, resin or wood having low heatproof temperature. [0100] (5) By regulation of the content of the polymerization initiator group-containing organosilane and the content of the second organosilane, the hardness and flexibility of the polymerization initiator layer are so optionally adjusted that said polymerization initiator layer can be formed even on a highly flexible substrate material such a sheet-form polymer, a metal film or paper, and it is possible to prevent the layer from cracking and peeling off the substrate material upon bending of the substrate material, etc. [0101] (6) The polymer brush layer polymerized out of a vinyl monomer may provide a cover over the surface of a variety of substrate materials. [0102] (7) Depending on the polymerization time and monomer species, it is possible to gain optional control of the thickness of the resultant polymer brush. [0103] (8) The polymer brush formed by the SI-ATRP process, because of being bonded to the aforesaid polymerization initiator layer by way of covalent bonding, is enhanced in terms of adherence and durability. [0104] (9) The aforesaid polymer brush, because of being capable of being formed at room temperature without recourse to heating treatment in particular, may be formed on the substrate material such as a polymer, paper, resin or wood having low heatproof temperature by way of the aforesaid polymerization initiator layer. [0105] (10) The aforesaid polymerization initiator layer and polymer brush, because of having high transparency, may impart functions to the surface of the substrate material without detrimental to design capability while the appearance of the substrate material to be treated remains intact. [0106] (11) The aforesaid polymerization initiator layer and polymer brush, because of being able to be formed and polymerized by various means inclusive of brushing in the air, do not impose any limitation on substrate material size. For instance, it is possible to treat large areas as by a roll-to-roll type having good mass productivity, and so on. [0107] (12) By optional changing of the monomer, the aforesaid polymer brush makes it possible to gain optional regulation of the wettability of its surface. [0108] (13) The present invention provides a novel method of achieving the formation of a polymer brush on a variety of large-area substrate materials, which has been considered difficult so far in the art. By the formation of the polymer brush, for instance, it is possible to provide a novel, more effective surface treatment technology capable of imparting functions to the surface of a substrate material, inclusive of improvements in the capability of removing raindrops out of glasses for automobiles and building materials, securing visibility by impartment of antifogging feature, preventing contaminations, controlling water flows through I-TASs, biochips or the like, controlling micro-water droplets (mist) through water-soluble ink jet nozzles or the like, preventing corrosion of metals/wood materials, improving the releasability of moldings out of nanoimprinting molds, and preventing adhesion of fingerprints on touch panel displays, and so on. [0109] (14) By making use of the catalyst carrying function of the polymer brush, it is possible to form a plating layer having enhanced adhesion on the surface of the substrate material, on which the polymer brush of the invention is provided.

EXAMPLES

[0110] By way of example but not by way of limitation, the present invention will now be explained in greater details with reference to the following preferable examples.

[0111] It is here understood that the mass of a solid material such as copper (II) chloride in each example is converted to, and indicated by, a part by volume on the basis of the density and purity of that material (commercially available).

Example 1

[0112] (chloromethyl)phenylethyltrimethoxysilane (0.0088, 0.141, 0.564 parts by volume; called Examples 1-1, 1-2, 1-3 in order) or (chloromethyl)phenyltrimethoxysilane (0.564 parts by volume; called Example 1-4) was added to a mixed solution comprising a 0.01M HCl aqueous solution (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and stirred at room temperature for 24 hours to prepare a precursor solution that, in turn, was added dropwise onto a silicon wafer, then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature for 24 hours to form polymerization initiator layer on the surface of the silicon wafer.

[0113] 2-(dimethylamino)ethyl methacrylate (5.5 parts by volume), copper (II) chloride (4 parts by volume), N,N,N,N,N-pentamethyldiethylenetriamine (7 parts by volume), sodium ascorbate (1 part by volume) and water (1 part by volume) were mixed into a polymerization solution. The aforesaid silicon wafer having the polymerization initiator layer formed on it was dipped in the polymerization solution for 2 hours to form a polymer brush on the surface of the substrate material.

[0114] The film thickness was measured by reflection spectroscopy using a microscope OPTELICS (registered trademark) HYBRID (Lasertec Co., Ltd.), and the static angle of contact of the polymer brush with water (2 L) was measured at room temperature with the use of a room-temperature automated contact angle meter DM-501Hi (Kyowa Interface Science Co., Ltd.). Here note that the film thickness was measured in one place of the polymerization initiator layer and that the value of the static angle of contact is indicated by an average worked out of measurements in three places of the polymerization initiator layer

[0115] The thicknesses of the obtained polymerization initiator layers, the results of measurement of the static angle of contact of the polymer brushes with water, and their appearances are set out in Table 1.

[0116] As shown in Table 1, it has been found that the obtained polymerization initiator layers are all transparent, and the thickness of the polymerization initiator layers depends on its composition (with the component ratios shown in the table), as measured by reflection spectroscopy.

TABLE-US-00001 TABLE 1 0.01M HCl TEOS EtOH CPTMS* CMPTS* (parts by (parts by (parts by (parts by (parts by Example 1 volume) volume) volume) volume) volume) 1-1 1 2.8 8 0.0088 1-2 1 2.8 8 0.141 1-3 1 2.8 8 0.564 1-4 1 2.8 8 0.564 Thickness Static of the Contact Initiator Angle of Layer Water Example 1 (nm) () Appearance 1-1 370 74.0 Transparent 1-2 420 72.3 Transparent 1-3 620 63.9 Transparent 1-4 570 62.6 Transparent CPTMS*: (chloromethyl)phenylethyltrimethoxysilane CMPTS*: (chloro)methylphenyltrimethoxysilane

Example 2

[0117] (Chloromethyl)phenylethyltrimethoxysilane and phenyltriethoxysilane (0.5076 parts by volume/0.0564 parts by volume, 0.3948 parts by volume/0.1692 parts by volume, 0.282 parts by volume/0.282 parts by volume; called Examples 2-1, 2-2, 2-3 in order) were added to a mixed solution comprising 0.01M HCl (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and stirred at room temperature for 24 hours to prepare a precursor solution that, in turn, was added dropwise onto a silicon wafer, then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature to form polymerization initiator layer on the surface of the silicon wafer.

[0118] 2-(Dimethylamino)ethyl methacrylate (5.5 parts by volume), copper (II) chloride (4 parts by volume), N,N,N,N,N-pentamethyldiethylenetriamine (7 parts by volume), sodium ascorbate (1 part by volume) and water (1 part by volume) were mixed into a polymerization solution. The aforesaid silicon wafer having the polymerization initiator layer formed on it was dipped in the polymerization solution for 2 hours to form a polymer brush on the surface of the substrate material.

[0119] The thickness of the obtained polymerization initiator layers, the results of measurements of the static contact angle of water of the polymer brushes with water, and their appearances are set out in Table 2.

[0120] As shown in Table 2, it has been found that the obtained polymerization initiator layers are all transparent.

TABLE-US-00002 TABLE 2 0.01M HCl TEOS EtOH CPTMS* PTES* (parts by (parts by (parts by (parts by (parts by Example 2 volume) volume) volume) volume) volume) 2-1 1 2.8 8 0.5076 0.0564 2-2 1 2.8 8 0.3948 0.1692 2-3 1 2.8 8 0.282 0.282 Thickness Static of the Contact Initiator Angle of Layer Water Example 2 (nm) () Appearance 2-1 580 67.8 Transparent 2-2 648 63.6 Transparent 2-3 647 56.0 Transparent CPTMS*: (chloromethyl)phenylethyltrimethoxysilane PTES*: phenyltriethoxysilane

Example 3

[0121] In the examples disclosed here, the silicon wafer of Examples 1 to 3 having the polymerization initiator layer formed on it was used to form various polymer brushes under the following conditions.

[0122] Various monomers set out in the following Table 3 (in the parts by volume set out in Table 3), copper (II) chloride (4 parts by volume), N,N,N,N,N-pentamethyldiethylenetriamine (7 parts by volume), sodium ascorbate (1 part by volume) and water or ethanol (1 part by volume) were mixed into a polymerization solution. The aforesaid silicon wafer having the polymerization initiator layer formed on it was dipped in the polymerization solution for 2 hours to form a polymer brush on the surface of the substrate material (Examples 3-1 to 3-16).

[0123] The results of measurement of the static angles of contact of the obtained polymer brushes with water and their appearances are set out in Table 3.

TABLE-US-00003 TABLE 3 Copper N,N N,N,N- Sodium Monomer Chloride triamine* Ascorbate Monomer (parts by (parts by (parts by (parts by Example 3 Substrate Species volume) volume) volume) volume) Substrate Silicon Not used Ex. 1-3 Ex. 1-3 Not used Ex. 3-1 Ex. 1-3 (1)* 5.5 4 7 1 Ex. 3-2 Ex. 1-3 (2)* 8.5 4 7 1 Ex. 3-3 Ex. 1-3 (3)* 4.7 4 7 1 Ex. 3-4 Ex. 1-3 (4)* 0.7 4 7 1 Ex. 3-5 Ex. 1-3 (5)* 1.8 4 7 1 Ex. 3-6 Ex. 1-3 (6)* 1.9 4 7 1 Ex. 3-7 Ex. 1-3 (7)* 2.1 4 7 1 Ex. 3-8 Ex. 1-3 (8)* 8.5 4 7 1 Ex. 3-9 Ex. 1-3 (9)* 0.2 4 7 1 Ex. 3-10 Ex. 1-3 (10)* 0.2 4 7 1 Ex. 3-11 Ex. 1-3 (11)* 3.8 4 7 1 Ex. 3-12 Ex. 1-3 (12)* 4.4 4 7 1 Ex. 3-13 Ex. 1-3 (13)* 0.3 4 7 1 Ex. 3-14 Ex. 1-3 (14)* 0.9/7.7 4 7 1 Ex. 3-15 Ex. 1-3 (14)* 4.3/4.3 4 7 1 Ex. 3-16 Ex. 1-3 (14)* 7.7/0.9 4 7 1 Solvent (parts by Static Contact Angle Example 3 volume) of Water () Appearance Substrate 1 <5 Transparent Ex. 1-3 1 83.6 Transparent Ex. 3-1 1 63.9 Transparent Ex. 3-2 1 70.5 Transparent Ex. 3-3 1 69.2 Transparent Ex. 3-4 1 27.5 Transparent Ex. 3-5 1 71.2 Transparent Ex. 3-6 1 12.9 Transparent Ex. 3-7 1 11.0 Transparent Ex. 3-8 1 89.2 Transparent Ex. 3-9 1 6.3 Transparent Ex. 3-10 1 6.6 Transparent Ex. 3-11 1 45.4 Transparent Ex. 3-12 1 39.7 Transparent Ex. 3-13 1 39.3 Transparent Ex. 3-14 1 83.2 Transparent Ex. 3-15 1 87.3 Transparent Ex. 3-16 1 88.2 Transparent N,N,N,N,N-triamine*: N,N,N,N,N-pentamethyldiethylene-triamine (1)*: 2-(dimethylamino)ethyl methacrylate (2)*: methyl methacrylate (3)*: 2-(diethylamino)ethyl methacrylate (4)*: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (5)*: N-isopropylacrylamide (6)*: sodium methacrylate (7)*: sodium acrylate (8)*: styrene (9)*: 3-sulfopropyl methacrylate potassium salt (10)*: 2-methacryloyloxyethylphosphorylcholine (11)*: 4-vinylpyridine (12)*: vinylimidazole (13)*: 4-vinylphenylboronic acid (14)*: methyl methacrylate and styrene

Example 4

[0124] In the examples described here, various substrate materials were used in place of the one (silicon wafer) of Example 1, and the amount of (chloromethyl)phenylethyltrimethoxysilane added was varied as described below to form a polymerization initiator layer under the following conditions (Examples 4-1 to 4-12).

[0125] (chloromethyl)phenylethyltrimethoxysilane was added in the same three amounts as in Examples 1-1, 1-2 and 1-3 and described in the following Table 4 to a mixed solution comprising 0.01M HCl aqueous solution (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and stirred at room temperature for 24 hours to prepare a precursor solution. This precursor solution was added dropwise onto the surfaces of various substrate materials (acrylic resin, polycarbonate, glass, and copper sheet), then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature for 24 hours to form polymerization initiator layers. A solution having the same composition as in Example 1 was used as the polymerization solution, and a two-hour polymerization was carried out in the polymerization solution.

[0126] The results of measurement of the static angle of contact of the polymer brushes with water on the polymerization initiator layer are indicated with their appearances in Table 4.

TABLE-US-00004 TABLE 4 (chloro- methyl)- phenyl- 0.01M ethyl- HCl TEOS EtOH trimeth- (parts (parts (parts oxysilane by by by (parts by Example 4 Substrate volume) volume) volume) volume) Ex. 4-1 Acrylic resin 1 2.8 8 0.0088 Ex. 4-2 Acrylic resin 1 2.8 8 0.141 Ex. 4-3 Acrylic resin 1 2.8 8 0.564 Ex. 4-4 Polycarbonate 1 2.8 8 0.0088 Ex. 4-5 Polycarbonate 1 2.8 8 0.141 Ex. 4-6 Polycarbonate 1 2.8 8 0.564 Ex. 4-7 Glass 1 2.8 8 0.0088 Ex. 4-8 Glass 1 2.8 8 0.141 Ex. 4-9 Glass 1 2.8 8 0.564 Ex. 4-10 Copper sheet 1 2.8 8 0.0088 Ex. 4-11 Copper sheet 1 2.8 8 0.141 Ex. 4-12 Copper sheet 1 2.8 8 0.564 Static Contact Angle of Example 4 Water () Appearance Ex. 4-1 67.1 Transparent Ex. 4-2 65.7 Transparent Ex. 4-3 66.6 Transparent Ex. 4-4 63.1 Transparent Ex. 4-5 63.4 Transparent Ex. 4-6 58.7 Transparent Ex. 4-7 62.2 Transparent Ex. 4-8 63.7 Transparent Ex. 4-9 60.3 Transparent Ex. 4-10 76.5 Transparent Ex. 4-11 74.5 Transparent Ex. 4-12 76.2 Transparent

Example 5

[0127] In the examples described here, the stirring time of the mixed solution in Examples 1 to 3 was varied, and the polymerization initiator layer was formed under the following conditions.

[0128] (chloromethyl)phenylethyltrimethoxysilane (0.564 parts by volume) was added to a mixed solution comprising 0.01M HCl aqueous solution (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and stirred at room temperature for 24 hours, 48 hours, 96 hours (called Examples 5-1, 5-2, 5-3 in order) to prepare a precursor solution. This precursor solution was added dropwise onto a silicon wafer, then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature for 24 hours to form a polymerization initiator layer. A solution having the same composition as in Example 1 was used as the polymerization solution, and a two-hour polymerization was carried out in the polymerization solution.

[0129] The results of measurement of the static angle of contact of the polymer brushes with water on the polymerization initiator layer are indicated with their appearances in Table 5.

TABLE-US-00005 TABLE 5 (chloromethyl)- phenyl- 0.01M ethyltrimeth- HCl TEOS EtOH oxysilane (parts by (parts by (parts by (parts by Example 5 volume) volume) volume) volume) Ex. 5-1 1 2.8 8 0.564 Ex. 5-2 1 2.8 8 0.564 Ex. 5-3 1 2.8 8 0.564 Static Contact Stirring Angle of Example 5 Time (hr.) Water () Appearance Ex. 5-1 24 80.9 Transparent Ex. 5-2 48 80.8 Transparent Ex. 5-3 96 80.6 Transparent

Comparative Example 1

[0130] Three organosilanes shown in Table 6 were used to form polymerization initiator layer (Comp. Ex. 1-1, 1-2, 1-3).

[0131] A glass bottle (1.5 mL) containing an organosilane (20 l) and various substrate materials (silicon wafer, acrylic resin, polycarbonate, glass, and copper sheet) were placed in a closeable Teflon (registered trademark) container (60 mL), and then heat treated at 100 C. for 24 hours thereby preparing a monomolecular film of the polymerization initiator. A solution having the same composition as in Example 1 was used as the polymerization solution, and a 24-hour polymerization was carried out in the polymerization solution.

[0132] As a result, it has been found that even with the three organosilanes shown in Table 6, a polymer brush can be formed when the substrate material is a silicon wafer, a glass, and a copper sheet. However, when using an acrylic resin or polycarbonate as the substrate material, its discoloration or deformation was observed as shown in Table 6, and when using (chloromethyl)phenyltrichlorosilane, there was no formation of any polymer brush observed.

TABLE-US-00006 TABLE 6 Comp. State of the Formation of the Ex. 1 Initiator Substrate Polymer Brush 1-1 (chloromethyl)phenyl- Yellowing, and Not formed trichlorosilane Deformation 1-2 (chloromethyl)phenyl- Discoloration Formed ethyltrimethoxysilane 1-3 (3-trimethoxysilyl)propyl Discoloration Formed 2-bromo-2-methyl propionate

Comparative Example 2

[0133] To form a polymerization initiator layer, 3-(trimethoxysilylpropyl)-2-bromo-2-methylpropionate (0.56 parts by volume) having a 2-bromoisobutyryl group that is a polymerization initiator group was added to a mixed solution comprising 0.01M HCl aqueous solution (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and then stirred at room temperature for 24 hours to prepare a precursor solution. This precursor solution was added dropwise onto a silicon wafer, then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature for 24 hours to form a polymerization initiator layer on the surface of a silicon wafer. A solution having the same composition as in Example 1 was used as the polymerization solution, and a 2-hour polymerization was carried out in the polymerization solution.

[0134] The state of the obtained substrate material, and whether or not the polymer brush was formed is shown in Table 7. With the initiator used in Comparative Example 2, there was no formation of any polymer brush found.

TABLE-US-00007 TABLE 7 State of the Formation of the Initiator Substrate Polymer Brush Comp. 3-(2-bromoisobutyryloxy)- Transparent Not formed Ex. 2 propyl-trimethoxysilane

Comparative Example 3

[0135] To form a polymerization initiator group, amino-propyltriethoxysilane (2.1 parts by volume) and 2-bromo-isobutyrylamide (1 part by volume) were mixed in hexane, and then stirred in an ice bath for 6 hours. After removal of the resulting white solid by filtration, the solvent was distilled off at reduced pressure to obtain 2-bromo-2-methyl-N-(3-triethoxysilyl)propyl)propanamide.

[0136] The resultant 2-bromo-2-methyl-N-(3-triethoxy-silyl)propyl)propanamide (0.56 parts by volume) was added to a mixed solution comprising 0.01M HCl aqueous solution (1 part by volume), TEOS (2.8 parts by volume) and EtOH (8 parts by volume), and then stirred at room temperature for 24 hours to prepare a precursor solution. This precursor solution was added dropwise onto a silicon wafer, then spin-coated (2000 rpm for 10 seconds), and then dried at room temperature for 24 hours to form a polymerization initiator layer on the surface of the silicon wafer.

[0137] The obtained silicon wafer having the polymerization initiator layer formed on it was dipped and polymerized in a polymerization solution having the same composition as in Example 1 for 2 hours to form a polymer brush on the surface of the substrate material.

[0138] The state of the obtained substrate material, and whether or not the polymer brush was formed is shown in Table 8. With the initiator used in Comparative Example 3, there was no formation of any polymer brush observed, or the polymerization initiator layer remained partly dissolved (as shown by dissolved in Table 8).

TABLE-US-00008 TABLE 8 State of the Formation of the Initiator Substrate Polymer Brush Comp. 3-(2-bromoisobutyryl- Transparent Not formed, or Ex. 3 amino)propyl- remaining triethoxysilane dissolved

[0139] From relative estimations of the surface features of samples prepared in the aforesaid Examples 1 to 5 and Comparative Examples 1 to 3, it has been found that Examples 1 to 5 wherein the polymerization initiator layer is formed by use of the precursor solution prepared by addition of the metal alkoxide to the organosilane make the uniformity of the resulting initiator layer higher than Comparative Examples 1 to 3 wherein a monomolecular film that provides polymerization initiator layer is formed by sole use of the organosilane without detrimental to the performance and design capability of the substrate material.

[0140] It has also been found that the polymer brush can be formed on the polymerization initiator layer containing the polymerization initiator prepared in Example 1, and 2 whereas, in Comparative Examples 1 to 3, it is difficult to form a polymer brush or, alternatively, the substrate material may undergo discoloration and deformation.

[0141] When a monomolecular film that provides polymerization initiator layer is formed by sole use of the organosilane, it is difficult to treat a surface having large roughness or a surface of a substrate material having low activity as generally known in the art. Indeed, as can also be seen from the results of Comparative Example 1, some polymer brush may be formed on a smooth substrate material having small roughness, such as glass or silicon, yet other substrate materials undergo discoloration or deformation or, alternatively, they are unable to yield any polymer brush.

[0142] Further, as can also be seen from Examples 1, 2, 4 and 5, the treatment technology of the invention has enhanced versatility in that uniform polymerization initiator layer can be formed with no need of special pretreatment or treatment conditions for substrate materials and without detrimental to the performance and design capability of substrate materials. The precursor solution of the invention is also so stable and has so a long pot life (it can be stored in a refrigerator over at least one month) that it is possible to easily form uniform polymerization initiator layer that remains stable over an extended period of time.

[0143] Further, as can also be seen from Example 3, uniform polymerization initiator layer can be formed with ease on a variety of substrate materials by the treatment technology disclosed herein so that a polymer brush can be formed from the surface of said polymerization initiator layer in the air, and said polymerization initiator layer and said polymer brush can be applied by brushing in the air so that large areas can be treated, too. In addition, the surface wettability of the substrate material may be controlled as desired, although depending on the monomer species used.

[0144] Furthermore, as can also be seen from Comparative Examples 2 and 3, ester bonds or amide bonds are cleft by way of hydrolysis to cause the polymerization initiator group to be not contained in the polymerization initiator layer or the polymer initiator layer to be dissolved during polymerization, resulting in a failure to form any polymer brush or no or little formation of any polymer brush.

Example 6

[0145] In the example described here, a bar coater made by Cotec Co., Ltd. was used to coat and dry a precursor solution by means of a bar coating process into a polymerization initiator layer.

[0146] A (1 mm thick, 500 mm wide, 500 mm long) glass and a (1 mm thick, 500 mm wide, 500 mm long) polycarbonate were used as the substrate material.

[0147] The polymerization initiator solution of Examples 1 to 3 was used for the precursor solution while diluted five-fold with ethanol. This precursor solution was added dropwise onto the substrate material, then coated by means of a bar coater, and then dried at room temperature for 24 hours to form polymerization initiator layer (having a thickness of 240 nm).

[0148] As a result of observation of the obtained polymerization initiator, it has been found that the polymerization initiator layer formed by the bar coater process is enhanced in terms of transparency irrespective of the dilution ratio of the precursor solution.

[0149] The results of measurement of the static angle of contact of the polymer brushes with water on the obtained polymerization initiator layer and their appearances are shown in Table 9.

TABLE-US-00009 TABLE 9 (chloro- methyl)- phenyl- 0.01M ethyl- HCl TEOS EtOH trimeth- (parts (parts (parts oxysilane by by by (parts by Example 6 Substrate volume) volume) volume) volume) Ex. 6-1 Glass 1 2.8 8 0.564 Ex. 6-2 Poly- 1 2.8 8 0.564 carbonate Static Contact Angle of Example 6 Water () Appearance Ex. 6-1 68.1 Transparent Ex. 6-2 64.0 Transparent

Example 7

[0150] In the example described herein, a roll-to-roll type film-making system was used to coat a precursor solution in the gravure mode for formation of polymerization initiator layer.

[0151] A roll film in which a polyester layer was formed on a 125 m thick, 400 mm wide, 100 m long) polyethylene terephthalate (PET) film excelling in flexibility as an easy-to-bond layer was used as a substrate material.

[0152] The polymerization initiator layer precursor solution of Examples 1 to 3, diluted 5-fold and 20-fold with isopropanol, was used as a precursor solution. This precursor solution was coated onto the film, and then dried at 80 C. for 1 minute to form a polymerization initiator layer (having a thickness of 59 nm).

[0153] As a result of observation of the obtained polymerization initiator layer, it has been found that the polymerization initiator layer formed on the surface of the PET film excels in transparency irrespective of the dilution ratio of the precursor solution, and the occurrence of cracks or the like has not been confirmed.

Example 8

[0154] In the example described here, a (297 mm by 210 mm) piece cut out of the substrate material covered with the polymerization initiator layer obtained in Example 7 was used, as mentioned below, to prepare a polymer brush.

[0155] A solution having the same composition as in Example 1 was used as a polymerization solution, and the cut piece was dipped in the polymerization solution for 2 hours to form a polymer brush on its surface.

[0156] As a result of observation of the obtained polymer brush, it has been found that the transparency of the PET film is kept intact with no confirmed occurrence of cracks or the like.

Example 9

[0157] In the example described here, the catalyst carrying function of the polymer brush was used to fix or graft a catalyst onto the surface of a substrate material and apply electroless copper plating thereto to form a plating layer thereon under the following conditions.

[0158] The PET film of Example 8 provided with a polymer brush was used as the substrate material that was then dipped in an acidic solution of 1.4 mM palladium (II) chloride for 2 hours to carry out adsorption of the palladium catalyst onto the polymer brush for the fixation of said catalyst.

[0159] Then, Thru-Cup (registered trademark) PEA made by Uyemura Co., Ltd. was used; an electroless copper plating aqueous solution comprising ion exchanged water (60 parts by volume), Thru-Cup PEA-40-M (10 parts by volume), Thru-Cup PEA-40-B (6 parts by volume), Thru-Cup PEA-40-D (3.5 parts by volume), and a 37% formaldehyde solution (2.3 parts by volume) was prepared, and the PET film, to which said palladium catalyst was fixed, was dipped in said aqueous solution for 1 hour to apply electroless copper plating treatment thereto.

[0160] It has consequently been confirmed that the copper plating layer adheres firmly to the polymer brush-side surface of the PET film.

INDUSTRIAL AVAILABILITY

[0161] According to the invention, it is possible to form the polymer brush having enhanced adherence on the surface of a variety of large-area substrate materials thereby giving the surface of the substrate material a variety of functions such as water/oil repellency, super-hydrophilicity, slippage capability, droplet removal capability, fingerprint resistance, antifogging capability, slidability, corrosion resistance, and antibacterial activity.

[0162] The present invention provides a method of achieving the formation of a polymer brush on a variety of large-area substrate materials, which has been considered difficult so far in the art. By the formation of the polymer brush by way of polymer initiator layer formed by the sol-gel process, for instance, it is possible to provide a novel, more effective surface treatment technology capable of imparting functions to the surface of a substrate material, inclusive of improvements in the capabilities of removing raindrops out of glasses for automobiles and building materials, securing visibility by impartment of antifogging features, preventing contaminations, controlling water flows through -TASs, biochips or the like, controlling micro-water droplets (mist) through water-soluble ink jetting nozzles or the like, preventing corrosion of metals/wood materials, improving the releasability of moldings out of nanoimprinting molds, and preventing adhesion of fingerprints on touch panel displays, etc.