PROCESS FOR MODIFICATION OF A SOLID SURFACE

Abstract

A process for the modification of a surface of a solid material, having the step of contacting the surface with a surface-modifying composition under irradiation with light of a wavelength in the range of 200 to 800 nm optionally in the presence of a photoinitiator, wherein the solid material has surface groups selected from COH, SiOH, CO and COC groups and wherein the surface-modifying composition has at least a hydrosilane and at least one reactive compound (A) other than the hydrosilane, wherein the reactive compound (A) has at least two functional groups selected from (meth)acrylate, (meth)acrylamide, hydroxyl, carboxylic acid, alkene, alkyne and epoxy, and wherein the amount of hydrosilane in the composition ranges between 0.5 and 99 vol %, and wherein the vol % is determined at 20 C. relative to the total of the surface modifying composition. A solid material having a partial surface modification layer.

Claims

1. A process for the modification of a surface of a solid material, comprising the step of: contacting the surface with a surface-modifying composition under irradiation with light of a wavelength in the range of 200 to 800 nm optionally in the presence of a photoinitiator, wherein the solid material has surface groups selected from COH, SiOH, CO and COC groups and wherein the surface-modifying composition comprises at least a hydrosilane and at least one reactive compound (A) other than the hydrosilane, wherein the at least one reactive compound (A) comprises at least two functional groups selected from (meth)acrylate, (meth)acrylamide, hydroxyl, carboxylic acid, alkene, alkyne and epoxy, and wherein the amount of the hydrosilane in the composition ranges between 0.5 and 99 vol %, and wherein the vol % is determined at 20 C. relative to the total of the surface modifying composition.

2. The process according to claim 1, wherein the amount of hydrosilane and the at least one reactive compound (A) are together between 10-100 vol % of the surface modifying composition and wherein the amount of the at least one reactive compound (A) ranges between 1 and 50 vol %.

3. The process according to claim 1, wherein the amount of the photoinitiator ranges between 0 and 5.0 wt. %, more preferably in the range of 0.001 to 1 wt. %, even more preferably in the range of 0.01 to 0.2 wt. %, and in particular in the range of 0.01 to 0.1 wt. %, relative to the surface-modifying composition.

4. The process according to claim 1, wherein the solid material is chosen from polyesters, polyethers, polyketones, polycarbonates, polyamides, polyurethanes, epoxyresins, polyalcohols, (meth)acrylate and (meth)acrylamide polymers, polyetherimides and silica containing solids.

5. The process according to claim 1, wherein the amount of the hydrosilane ranges from 50-99 vol %, the at least one reactive compound (A) ranges from 1-50 vol %, the amount of solvent ranges from 0-30 vol %, and wherein the at least one reactive compound (A) is a hydrophobic compound having aliphatic or fluorinated substituents.

6. The process according to claim 1, wherein the amount of the hydrosilane ranges between 1 and 50 vol %, the amount of the at least one reactive compound (A) ranges between 5 and 50 vol %, and the amount of the solvent ranges between 5 and 85 vol %, wherein the at least one reactive compound (A) is PEGylated.

7. The process according to claim 1, wherein the hydrosilane is represented by any of the hydrosilanes according to formula I), II) or III), ##STR00027## wherein R.sup.cH or methyl, wherein R.sup.a is H, optionally substituted C.sub.1-30 alkyl, optionally substituted C.sub.2-30 alkenyl, optionally substituted C.sub.2-30 alkynyl, optionally substituted 6-20 aralkyl, optionally substituted C.sub.6-10 aryl, or a polymeric moiety having a molecular weight of about 1000 to about 100,000, wherein each of R.sup.b and X is, independently, optionally substituted C.sub.1-30 alkyl, optionally substituted C.sub.2-30 alkenyl, optionally substituted C.sub.2-30 alkynyl, optionally substituted C.sub.6-20 aralkyl, optionally substituted C.sub.6-10 aryl, or a polymeric moiety having a number average molecular weight of about 1000 to about 100,000, wherein the polymeric moiety is selected from the group consisting of hydrocarbon polymers, polyesters, polyamides, polyethers, polyacrylates, polyurethanes, epoxides, polymethacrylates and polysiloxanes (e.g. poly(methylhydrosiloxane)), wherein l=2-10, preferably 2-4 and k=3-6, preferably 3-4.

8. The process according to claim 7, wherein the hydrosilane having a single hydrosilyl group include compounds represented by ##STR00028## where at least one of R.sup.a, R.sup.b is a group represented by the formula selected from the following list of substituents 100-194 and the remaining R.sup.a, R.sup.b, is independently chosen from the groups as described above (e.g. C.sub.1-C.sub.30 alkyl), wherein the list consists of: ##STR00029## ##STR00030## ##STR00031## ##STR00032##

9. The process according to claim 7, wherein the hydrosilane having at least two hydrosilyl groups is a compound selected from the following list of hydrosilanes with reference 200-263: ##STR00033## ##STR00034## ##STR00035## ##STR00036## ##STR00037##

10. The process according to claim 1, wherein the at least one reactive compound (A) comprises at least two hydroxyl groups or the at least one reactive compound (A) comprises at least one (meth)acrylate and/or one (meth)acrylamide as one type of reactive group and at least one hydroxyl group as second type of reactive group.

11. The process according to claim 1, wherein the at least one reactive compound (A) is a compound selected from the following list of compounds 300-375, wherein n ranges between 1 and 20 and m ranges between 1 and 1000: ##STR00038## ##STR00039## ##STR00040## ##STR00041## ##STR00042## ##STR00043## ##STR00044## ##STR00045##

12. The process according to claim 1, wherein the surface-modifying composition comprises a. a hydrosilane according to formula 100, 182, 200-202, 230-232, 250, 251 or mixtures thereof and a reactive compound according to formula 300, 301, 303, 350, 360-365 or mixtures thereof and optionally a photoinitiator, nanoparticles and solvent; b. a hydrosilane according to anyone of formulas 120, 121, 150-155, 180, 181, 240-242, 250-253, 261 and a reactive compound (A) according to one of the formula 306, 310-312, 345, 351, 370, 371 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent; c. a hydrosilane according to anyone of formulas 110, 194, 210-212, 230-232, 250, 251, 262 and a reactive compound (A) according to one of the formula 330, 331, 352, 372, 373 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent; d. a hydrosilane according to anyone of formulas 110, 111, 194, 220-222, 250, 251, 263 and a reactive compound (A) according to one of the formula 332, 333, 353, 374, 375 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent; e. a hydrosilane according to formula 100, 182, 200-202, 230-232, 250, 251 or mixtures thereof and a reactive compound according to formula 300, 301, 303, 305, 350, 360-365 or mixtures thereof and optionally a photoinitiator, nanoparticles and solvent; f. a hydrosilane according to anyone of formulas 120, 121, 150-155, 180, 181, 240-242, 250-253, 261 and a reactive compound (A) according to one of the formula 306, 310-312, 345, 351, 370, 371 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent; g. a hydrosilane according to anyone of formulas 110, 194, 210-212, 230-232, 250, 251, 262 and a reactive compound (A) according to one of the formula 330, 331, 352, 372, 373 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent; or h. a hydrosilane according to anyone of formulas 110, 111, 194, 220-222, 250, 251, 263 and a reactive compound (A) according to one of the formula 332, 333, 353, 374, 375 or mixtures thereof and optionally photoinitiator, nanoparticles and solvent.

13. The process according to claim 1, wherein the surface-modifying composition comprises microparticles and/or nanoparticles, wherein preferably, the microparticles and nanoparticles have a number average diameter of 0.1 nm to 10 m, 1 nm to 1 m or 10 nm to 100 nm, as determined according to SEM.

14. The solid material having partially a surface modification layer obtainable by the process according to claim 1, wherein the thickness of the surface modification layer ranges between 10 nm and 1000 nm as measured with ellipsometry.

15. The solid material of claim 14, wherein the Water Contact Angle (WCA) of the surface modification layer ranges between 100 and 180.

16. The solid material of claim 14, wherein the surface of the solid material has parts which are non-irradiated, which non-irradiated parts do not contain compounds of the surface-modifying composition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0100] FIG. 1AFM height image of a 50 m wide surface modification layer line on glass (a) and the corresponding height profile (b).

[0101] FIG. 2SEM images of a 50 m wide surface modification layer line on glass at a magnification of 2.500 (a) and 100,000 (b).

[0102] FIG. 3ellipsometric height image of 50 m wide surface modification layer lines on glass (a) and the corresponding height profile (b).

DETAILED DESCRIPTION OF THE INVENTION

[0103] The invention is now elucidated by way of the following examples, without however being limited thereto.

Examples

[0104] General

[0105] Materials

[0106] Commercially available hydrosilanes and solvents were obtained from Sigma-Aldrich or Gelest. When needed, compounds were purified using Kugelrohr vacuum distillation. Hydrosilanes that are not commercially available were synthesized by reduction of the corresponding chlorosilanes with LiAlH.sub.4 using a procedure adapted from literature.

[0107] Surface Modification

[0108] Samples were cleaned by rinsing and ultrasonication in an appropriate solvent. Optionally, samples were exposed to a low pressure oxygen plasma to create hydroxyl groups and/or other oxidized species (e.g. aldehydes, ketones, carboxylic acids) on the surface. The sample was placed on a custom-made sample holder and a volume of the surface-modifying composition was deposited on the surface. Then, the sample was covered by a photomask, resulting in a uniform liquid film between the sample and the photomask. To demonstrate the principle of photochemical surface modification a very simple photomask was used with which half of the sample is irradiated, and the other half is not. Next, the sample was irradiated with UV light at an intensity of 10-15 mW/cm.sup.2, using a collimated light source. After completion of the reaction samples were rinsed to remove the excess of the surface-modifying composition and ultrasonicated with a suitable solvent. Finally, samples were dried in a stream of nitrogen.

[0109] Surface Characterization

[0110] Samples were analyzed by static water contact angle (WCA) measurements using a Krss DSA-100 goniometer. Using the automated dispensing unit, 3 L water droplets were deposited on the surface, images were captured using a digital camera and analyzed using a suitable fitting algorithm, depending on the wettability of the surface.

[0111] The thickness of the surface modification layer was determined by spectroscopic imaging ellipsometry, using an EP4 ellipsometer (Accurion GmbH). The ellipsometric parameters and were determined in the spectral range between 400 and 900 nm at an angle of incidence of 50. For calculation of the layer thickness, an optical model of the sample needs to be created and fitted to the experimental data. A three-layer model was used, consisting of (1) the substrate, (2) the surface modification layer and (3) air (ambient). The optical properties of the substrate were determined experimentally by measuring and for a non-modified substrate. The Cauchy model is commonly used in ellipsometry for modelling thin non-absorbing organic films. In this model, the wavelength-dependent refractive index n() of the layer is given by:

[00001]$n\left(\right)=A_n+\frac{B_n}{{}^2}$

[0112] In some cases, the simple Cauchy model gave good fit results with A.sub.n=1.500.05 and B.sub.n between 10.sup.3 and 10.sup.4 nm.sup.2. For other samples, good fit results were only obtained when the surface modification layer was modelled using a model for porous materials (Bruggeman effective medium approximation) allowing for the presence of a fraction of air of 5010% in the Cauchy layer.

[0113] Molecular Structures and Abbreviations

[0114] Substrates

##STR00021## ##STR00022##

[0115] Hydrosilanes

##STR00023##

[0116] Reactive Compound (A)s

##STR00024##

[0117] Solvents and Other Components

##STR00025##

TABLE-US-00001 reactive compound other UV WCA WCA WCA plasma hydrosilane (A) component solvent time () () () non- Experiment # Substrate oxidation type conc.sup.1 type conc.sup.1 type conc.sup.2 type conc.sup.1 min non-treated irradiated irradiated 1a glass yes dihydro-F.sub.17 99 F.sub.17OH-Acr 1 15 121 30 1b glass yes dihydro-F.sub.17 95 F.sub.17OH-Acr 5 15 142 24 1c glass yes dlihydro-F.sub.17 90 F.sub.17OH-Acr 10 15 142 30 1d glass yes dihydro-F.sub.17 80 F.sub.17OH-Acr 20 15 135 45 1e (control).sup.3 glass yes dihydro-F.sub.17 100 15 108 20 1f (control).sup.3 glass yes dihydro-F.sub.17 90 F.sub.17-Acr 10 15 114 20 1g (control) glass yes F.sub.17OH-Acr 10 FC70 90 15 35 30 2 glass yes dihydro-F.sub.17 90 F.sub.17OH-MAcr 10 15 131 33 3a glass yes dihydro-F.sub.17 89 F.sub.17OH-Acr 10 BP 1 5 140 32 3b (control) glass yes F.sub.17OH-Acr 10 BP 1 FC70 89 15 38 30 4 glass yes trihydro-PEG 45 PEG.sub.9-OH-Acr 5 DGDE 50 15 44 31 5 glass yes TMCTS 8 PEG.sub.9-OH-Acr 8 DGDE 84 15 38 25 6 Si/SiO.sub.2 yes dihydro-F.sub.17 89 F.sub.17OH-Acr 10 BP 1 15 132 75 7 epoxide no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 5 140 55 8 SU-8 no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 30 75 (lit.) 130 9a COC yes trihydro-F.sub.17 99 F.sub.17OH-Acr 1 30 95 107 65 9b COC yes trihydro-F.sub.17 97.5 F.sub.17OH-Acr 2.5 30 105 59 9c COC yes trihydro-F.sub.17 95 F.sub.17OH-Acr 5 30 115 62 9d COC yes trihydro-F.sub.17 92.5 F.sub.17OH-Acr 7.5 30 110 66 9e COC yes trihydro-F.sub.17 90 F.sub.17OH-Acr 10 30 115 65 10a COC yes dihydro-PEG 45 PEG.sub.9-OH-Acr 45 DGDE 10 30 44 66 10b COC yes dihydro-PEG 45 PEG.sub.3-OH-Acr 45 DGDE 10 30 37 66 11a PC no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 30 78 135 11b (control) PC no dihydro-F.sub.17 90 F.sub.17-Acr 10 30 78 77 11c (control) PC no F.sub.17OH-Acr 10 FC70 90 30 79 84 12 PMMA no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 30 75 (lit.) 135 13 PEEK no trihydro-F.sub.17 95 F.sub.17OH-Acr 5 15 70 (lit.) 130 14 cellulose no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 15 <10 140 <10 15a nitrocellulose no dihydro-F.sub.17 89 F.sub.17OH-Acr 10 BPF.sub.10 1 <1 135 <10 15b nitrocellulose no dihydro-F.sub.17 90 F.sub.17OH-Acr 10 45 132 <10 15c (control) nitrocellulose no F.sub.17OH-Acr 10 BPF.sub.10 1 FC70 89 <1 <10 <10 UV thickness WCA () plasma hydrosilane reactive compound (A) other component solvent time (nm) WCA () non- example # substrate oxidation type conc (vol %) type conc (vol %) type conc type conc vol (%) min ellipsometry irradiated irradiated 16 glass yes trihydro-F.sub.17 45 F.sub.17OH-Acr 5 PFPE-Acr 25 mg/ml TFT(aq) 50 10 110 43 17 glass yes trihydro-F.sub.17 45 F.sub.17OH-Acr 5 PFPE-Acr 25 mg/ml TFT 50 10 125 50 18 glass yes trihydro-F.sub.17 45 F.sub.17OH-Acr 5 PFPE-Acr 25 mg/ml DMP 50 10 140 62 19 glass yes trihydro-F.sub.17 45 F.sub.17OH-Acr 5 PFPE-Acr 25 mg/ml DGDE 50 10 133 50 20 glass yes trihydro-C.sub.6 23 F.sub.17OH-Acr 5 DMP 72 15 51 139 21 glass yes TMDS 26 F.sub.17OH-Acr 5 DMP 69 15 68 142 22 glass yes trimethoxysilane 18 F.sub.17OH-Acr 5 DMP 77 15 51 132 23 glass yes PEG.sub.3-(dihydro).sub.2 48 F.sub.17OH-Acr 5 DMP 47 15 23 130 24 glass yes TMCTS 10 F.sub.17OH-Acr 10 PFPE-Acr 25 mg/ml TFT(aq) 80 15 124 35 25 glass yes TMCTS 10 F.sub.17OH-Acr 1 PFPE-Acr 25 mg/ml TFT(aq) 89 15 80 40 26 glass yes TMCTS 24 HO-PEG.sub.2-MAcr 9 DGDE 67 15 13 70 56 27 glass yes PEG.sub.3-(dihydro).sub.2 48 HO-PEG.sub.9-MAcr 7 DGDE 45 15 7 54 28 glass yes PEG.sub.3-(dihydro).sub.2 48 HO-PEG.sub.9-MAcr 7 F.sub.5EtOH 45 15 80 64 29 COC yes TMCTS 5 acrylic acid 22.5 DMA-MAcrAm 22.5 vol % DGDE 50 5 17 47 30 PP yes TMCTS 5 acrylic acid 22.5 DMA-MAcrAm 22.5 vol % DGDE 50 5 38 95 31 COC yes TMCTS 5 PEG-diepoxide 18 HMP 1 wt % DGDE 77 30 62 48 32 quartz no TMCTS 40 amino trialkyne 40 TFT 20 30 17 86 64 .sup.1concentrations are in vol % .sup.2concentration are in wt %

Examples 1-3: Hydrophobic Surface Modification of Glass

[0118] Glass microscope slides were cleaned by ultrasonication in acetone and isopropanol and activated by piranha solution and plasma oxidation to increase the number of silanol groups at the surface. Surface modification was carried out according to the general procedure as described above, using different concentrations and ratios of dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A).

[0119] In examples 1a-d, it is shown that for various compositions, 15 minutes UV irradiation is sufficient to drastically increase the hydrophobicity of the surface (WCA>120 for all compositions, >130 for concentrations F.sub.17OH-Acr above 1%), while the non-irradiated part of the sample remains hydrophilic (WCA approximately 30).

[0120] In Example 1e-f are similar to or based on the invention disclosed in PCT/EP2017/069608. In example 1e, it is shown that with pure dihydro-F.sub.17, i.e. without addition of a reactive compound (A) or photoinitiator, 15 minutes UV irradiation leads to a hydrophobic surface having a WCA of 108, while the non-irradiated part of the sample remains hydrophilic. Example 1f is similar to example 1c, the only difference being the use of mono-reactive F.sub.17-Acr instead of the multi-reactive F.sub.17OH-Acr. This clearly demonstrates the surprisingly different surface modification result. With F.sub.17-Acr (example 1f) a WCA of 114 was obtained, while with F.sub.17OH-Acr a much higher WCA of 142 was obtained, while for both the non-irradiated surface remains hydrophilic.

[0121] In example 1g, it is shown that the presence of a hydrosilane is required for the surface modification to take place. If the hydrosilane (in this case dihydro-F.sub.17) is replaced by the inert fluorinated solvent FC-70, no significant surface modification takes place and the surface remains hydrophilic (WCA of <35) on the entire substrate.

[0122] In example 2, it is shown that instead of F.sub.17OH-Acr, the corresponding methacrylate F.sub.17OH-MAcr may also be used without a significant change of the result.

[0123] In example 3a, it is shown that additional components may be added to the surface-modifying composition. In this case, 1 wt. % of a photoinitiator is added to the composition and the irradiation time is decreased to 5 minutes. Also this composition leads to a highly hydrophobic surface on the irradiated part of the sample, while the non-irradiated part remains hydrophilic.

[0124] In example 3b, it is shown that the presence of a hydrosilane is required for the surface modification to take place, even when 1 wt. % of photoinitiator is present. If the hydrosilane (in this case dihydro-F.sub.17) is replaced by the inert fluorinated solvent FC-70 with 1 vol % photoinitiator no significant surface modification takes place and the surface remains hydrophilic (WCA of <38) on the entire substrate.

##STR00026##

[0125] Also, surface modification with dihydro-F.sub.17 and F.sub.17-Acr according to PCT/EP2017/069608 leads to a very thin hydrophobic layer (<5 nm based on XPS data). In contrast, surface modification with dihydro-F.sub.17 and F.sub.17OH-Acr according to the current invention leads to a much thicker hydrophobic layer with a high degree of surface roughness and porosity. This was shown by further analysis of the samples by AFM, SEM and ellipsometry. For these experiments, a photomask with a line pattern was used for surface modification, resulting in parallel surface modification layer lines with a width of 50 m, separated by a distance of 100 m.

[0126] FIG. 1a shows the topography image of a surface modification layer line (width 50 m) as measured by AFM. This image shows that the width of the surface modification layer line corresponds well with the width of the irradiated area according to the design of the photomask, showing that patterned surface modification can be achieved with a good spatial resolution by the process according to the invention. FIG. 1b shows the height profile measured along the dashed line indicated in FIG. 1a. This profile shows that the thickness of the surface modification layer is approximately 90 nm, measured in the centre of the line. Near the edges of the line, the surface modification layer is thicker by 20-30 nm. Also, the profile indicates that the surface of the modification layer is not smooth, but contains a significant amount of roughness. For the area indicated by the rectangle in FIG. 1a, a surface roughness (R.sup.a) of 11 nm was calculated.

[0127] To avoid charging issues during SEM imaging, a thin layer of Tungsten was deposited on the samples by sputtering. FIG. 2a shows a SEM image of a surface modification layer line (width 50 m) at a magnification of 2,500. This image confirms the formation of a patterned surface modification layer with a good spatial resolution by the process according to the invention, in good agreement with the AFM image shown in FIG. 1a. Furthermore, the image indicates that on a microscopic level the surface modification layer is not homogeneous and dense, but it contains a microstructure. This is more clearly visible in FIG. 2b, which shows a smaller area of the same line at a magnification of 100,000. This image clearly shows that there is a high degree of surface roughness and porosity, in agreement with the AFM results.

[0128] Samples were also investigated by spectroscopic imaging ellipsometry. FIG. 3a shows an ellipsometric height image of three 50 m wide lines. FIG. 3b shows the corresponding height profile. Again, the result confirms the formation of a patterned surface modification with a good spatial resolution.

[0129] The height profile shown in FIG. 3b shows that the thickness of the layer is approximately 85 nm, measured in the centre of the line. Near the edges of the line, the surface modification layer is thicker by approximately 10 nm. When comparing the height profiles obtained by AFM (FIG. 1b) and ellipsometry (FIG. 3b), it can be concluded that the results from both techniques are in reasonable agreement.

Examples 4-5: Surface Modification of Glass with PEG

[0130] Glass microscope slides were cleaned by ultrasonication in acetone and isopropanol and activated by plasma oxidation to increase the number of silanol groups at the surface. Surface modification was carried out according to the general procedure as described above, using two different hydrosilanes in combination with PEG.sub.9-OH-Acr as the reactive compound (A).

[0131] In example 4, a surface-modifying composition of trihydro-PEG, PEG.sub.9-OH-Acr and DGDE is used. After 15 minutes of UV irradiation, the irradiated part of the surface has a WCA of 44, a typical value for PEG-modified surfaces. The non-irradiated part has a WCA of 31, indicating that no significant surface modification has taken place.

[0132] In example 5, the hydrosilane TMCTS is used in a surface-modifying composition further consisting of PEG.sub.9-OH-Acr and DGDE. After 15 minutes of UV irradiation, the irradiated part of the surface has a WCA of 38, a typical value for PEG-modified surfaces. The non-irradiated part has a WCA of 25, indicating that no significant surface modification has taken place.

Example 6: Hydrophobic Surface Modification of Oxidized Silicon(111)

[0133] Silicon (111) substrates were cleaned by ultrasonication in acetone and isopropanol and activated by plasma oxidation to increase the number of silanol groups at the surface. Surface modification was carried out according to the general procedure as described above, using a surface-modifying composition consisting of dihydro-F.sub.17 as the hydrosilane, F.sub.17OH-Acr as the reactive compound (A) and 1 wt. % of benzophenone (BP). After 15 minutes of UV irradiation, WCA on the irradiated part of the sample increased to 132. The non-irradiated part of the sample has a WCA of 75. Even though the non-irradiated part of the sample has also become more hydrophobic, there is still a significant difference in the hydrophobicity between the irradiated and non-irradiated areas.

Example 7-8: Hydrophobic Surface Modification of Surfaces with Epoxide Groups

[0134] In example 7, glass surfaces with epoxide groups were prepared. For this purpose, glass microscope slides were treated with an epoxysilane according to a silanization procedure adapted from literature. Samples were cleaned by ultrasonicating in acetone for 5 minutes. Samples were dried using a stream of nitrogen and subsequently placed in an oven at 140 C. for 5 minutes. Then, samples were exposed to a low pressure O.sub.2 plasma for 5 minutes and immediately immersed in a 2% (v/v) solution of (3-glycidyloxypropyl)trimethoxysilane in hexane for 2 hours. After silanization, samples were cleaned by 5 minutes ultrasonication in acetone and drying in a stream of nitrogen. After this silanization procedure, the epoxide-terminated surfaces have a WCA of 55.

[0135] Surface modification was carried out according to the general procedure as described above, using a surface-modifying composition consisting of dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A). After 5 minutes of UV irradiation, WCA on the irradiated part of the sample increased to 140, while WCA on the non-irradiated part remained unchanged at 56.

[0136] In example 8, SU-8 was used as the substrate. SU-8 is a polymer with epoxy groups on its surface. SU-8 samples were cleaned by ultrasonication in isopropanol and dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using a surface-modifying composition consisting of dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A). After 30 minutes of UV irradiation, WCA on the irradiated part of the sample increased to 130, much higher than the WCA of non-modified SU-8 (75).

Example 9: Hydrophobic Surface Modification of COG

[0137] COC samples were cleaned by ultrasonication in acetone, followed by exposure to a low pressure O.sub.2 plasma to create hydroxyl groups on the surface. After thorough rinsing with deionized water, samples were dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using different concentrations and ratios of trihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A) (examples 9a-e).

[0138] After 30 minutes of UV irradiation, the irradiated part of the sample has a WCA of between 105 and 115, significantly higher than the WCA on the non-irradiated area (60-65). Note that the relatively low WCA on the non-irradiated side is caused by the plasma oxidation, which results in a decrease of the WCA of COC from approximately 95 to 65. Therefore, the surface modification has resulted in a significant increase of the hydrophobicity also compared to non-oxidized COC.

Example 10: Surface Modification of COC with PEG

[0139] COC samples were cleaned by ultrasonication in acetone, followed by exposure to a low pressure O.sub.2 plasma to create hydroxyl groups on the surface. After thorough rinsing with deionized water, samples were dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using dihydro-PEG as the hydrosilane in combination with PEG.sub.9-OH-Acr and PEG.sub.3-OH-Acr as the reactive compounds (A).

[0140] In example 10a, a surface-modifying composition of dihydro-PEG, PEG.sub.9-OH-Acr and DGDE is used. After 30 minutes of UV irradiation, the irradiated part of the surface has a WCA of 44, a typical value for PEG-modified surfaces. The non-irradiated part has a WCA of 66, indicating that no significant surface modification has taken place. Note that the relatively low WCA on the non-irradiated side is caused by the plasma oxidation, which results in a decrease of the WCA of COC from approximately 95 to 65.

[0141] In example 10b, a surface-modifying composition of dihydro-PEG, PEG.sub.3-OH-Acr and DGDE is used. After 30 minutes of UV irradiation, the irradiated part of the surface has a WCA of 37, a typical value for PEG-modified surfaces. The non-irradiated part has a WCA of 66, indicating that no significant surface modification has taken place. Note that the relatively low WCA on the non-irradiated side is caused by the plasma oxidation, which results in a decrease of the WCA of COC from approximately 95 to 65.

Examples 11: Hydrophobic Surface Modification of Polycarbonate

[0142] Polycarbonate samples were cleaned by ultrasonication in isopropanol and dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A).

[0143] In example 11a, it is shown that after 30 minutes of UV irradiation, the WCA on the irradiated part of the sample is >130, a large increase in hydrophobicity compared to non-treated polycarbonate (WCA 78).

[0144] In this example, no surface activation by O.sub.2 plasma was done before surface modification, so no hydroxyl groups were created at the surface. Polycarbonate itself does not have any COH groups. Still the surface is successfully modified, indicating that the presence of COH groups on the surface is not a requirement for photochemical surface modification according to the invention.

[0145] A control experiment with monofunctional additive F.sub.17-Acr instead of the bifunctional reactive compound F.sub.17OH-Acr was done, indicated in the table as example 11b (control). In this case, no surface modification takes place and the WCA remains unchanged on the entire substrate.

[0146] In example 11c, it is shown that the presence of a hydrosilane is required for the surface modification to take place. If the hydrosilane (in this case dihydro-F.sub.17) is replaced by the inert fluorinated solvent FC-70, no significant surface modification takes place, resulting in similar values of the WCA on the entire substrate.

Examples 12: Hydrophobic Surface Modification of PMMA

[0147] PMMA samples were cleaned by ultrasonication in isopropanol and dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A).

[0148] After 30 minutes of UV irradiation, the WCA on the irradiated part of the sample is >130, a large increase in hydrophobicity compared to non-treated PMMA (WCA 75).

[0149] In this example, no surface activation by O.sub.2 plasma was done before surface modification, so no hydroxyl groups were created at the surface. PMMA itself does not have any COH groups. Still the surface is successfully modified, indicating that the presence of COH groups on the surface is not a requirement for photochemical surface modification according to the invention.

Example 13: Hydrophobic Surface Modification of PEEK

[0150] PEEK samples were cleaned by ultrasonication in isopropanol and dried using a stream of nitrogen. Surface modification was carried out according to the general procedure as described above, using trihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A).

[0151] After 15 minutes of UV irradiation, the WCA on the irradiated part of the sample is >120, a large increase in hydrophobicity compared to non-treated PEEK (WCA 70).

[0152] In this example, no surface activation by O.sub.2 plasma was done before surface modification, so no hydroxyl groups were created at the surface. PEEK itself does not have any COH groups. Still the surface is successfully modified, indicating that the presence of COH groups on the surface is not a requirement for photochemical surface modification according to the invention.

Examples 14-15: Hydrophobic Surface Modification of (Nitro)Cellulose

[0153] Surface modification of cellulose and nitrocellulose was carried out according to the general procedure as described above, using dihydro-F.sub.17 as the hydrosilane and F.sub.17OH-Acr as the reactive compound (A).

[0154] In example 14, it is shown that after 15 minutes of UV irradiation, the cellulose has become highly hydrophobic (WCA>130). On the non-irradiated area of the sample no WCA can be measured, since the water droplet is absorbed by the porous hydrophilic substrate (WCA<10).

[0155] In example 15a, it is shown that nitrocellulose already becomes highly hydrophobic (WCA>130) after less than 1 minute of UV irradiation if 1 wt. % of BPF.sub.10 is added to the surface-modifying composition as a photoinitiator. Again on the non-irradiated area of the sample no WCA can be measured.

[0156] In example 15b, it is shown that nitrocellulose can also be made hydrophobic without the addition of the photoinitiator. However, this requires a much longer UV irradiation time of 45 minutes. The non-irradiated area remains highly hydrophilic as the water droplet is absorbed by the porous substrate.

[0157] In example 15c, it is shown that the presence of a hydrosilane is required for the surface modification to take place. If the hydrosilane (in this case dihydro-F.sub.17) is replaced by the inert fluorinated solvent FC-70 with 1 wt. % of photoinitiator, no significant surface modification takes place and the surface remains hydrophilic and the water droplet is absorbed by the porous substrate (WCA<10).

Examples 16-25: Hydrophobic Surface Modification of Glass

[0158] Examples 16-19 show that the surface modification composition may comprise a variety of solvents. When DMP is used as a solvent, the highest WCA is obtained. However, also other solvents such as TFT and DGDE may be used. Even when water-saturated TFT is used (indicated as TFT(aq) in the table), a WCA of 110 is obtained, showing that the presence of water in the surface modifying composition does not prevent the formation of a hydrophobic surface modification layer. In examples 20-23, it is shown that a variety of hydrosilanes may be used for surface modification. All used hydrosilanes yield a surface modification layer with a thickness of several tens of nm and WCA values of >130 in combination with F.sub.17OH-Acr as the reactive compound (A), also when the hydrosilane does not contain a hydrophobic group. Examples 24 and 25 show that the surface modifying composition may comprise a large amount of solvent and still result in the formation of a hydrophobic surface modification layer.

Examples 26-28: Surface Modification of Glass with PEG

[0159] In examples 26-28, glass surfaces are modified using different surface modifying compositions, all comprising HO-PEG.sub.9-MAcr as the reactive compound (A). Ellipsometry clearly shows the presence of a surface modification layer. In comparison with examples 4 and 5, in which PEG.sub.9-OH-Acr is used, these examples show that the second type of reactive group in the reactive compound (A), in this case the hydroxy group, may be present at different positions in the molecule with respect to the first type of reactive group, in this case the (meth)acrylate group. Furthermore, these examples show that HO-PEG.sub.9-MAcr may be used in surface modifying compositions comprising different hydrosilanes and different solvents.

Examples 29-30: Hydrophilic Surface Modification of COC and PP

[0160] The surface modification described in examples 29 and 30, using acrylic acid as the reactive compound (A), result in a strong decrease of the WCA when applied to COC and PP, two hydrophobic polymers.

Examples 31-32: Reactive Compounds (A) without Acrylate Group

[0161] Example 31 shows the formation of a surface modification layer on COC using PEG-diepoxide as reactive compound (A). Due the highly similar optical properties of the substrate and the surface modification layer, accurate determination of layer thickness by ellipsometry was not possible. However, XPS analysis of the modified surface shows the presence of Si and ether carbons (COC), indicating that both TMCTS and PEG-diepoxide are incorporated in the surface modification layer.

[0162] In example 32, a surface modification layer is prepared on a quartz substrate using amino-trialkyne as the reactive compound (A). The surface modification layer has a thickness (determined by ellipsometry) of 17 nm. These examples show that surface modification layers can be prepared using reactive compounds (A) that contain only epoxide or alkyne groups, and do not contain polymerisable unsaturated groups (such as acrylate groups).