ANTIMICROBIAL AND/OR ANTIVIRAL POLYMER SURFACES

Abstract

A polymer substrate having deposited on its surface a reaction product of a precursor material obtained or obtainable by a method for preparation of polymer, and to the use of the polymer having improved antibacterial properties and/or antiviral properties or of the polymer having improved antibacterial properties and/or antiviral properties obtained or obtainable by the method for medical applications, antibiofouling applications, hygiene applications, food industry applications, industrial or computer related applications, consumer goods applications and appliances, public and public transport applications, underwater, water sanitation or seawater applications.

Claims

1.-14. (canceled)

15. A method for preparation of a polymer material having improved antibacterial properties and/or antiviral properties comprising: a) providing a polymer substrate having a surface; b) generating a plasma under near atmospheric conditions by passing a carrier gas through an excitation zone and by applying high frequency alternating current to an electrode positioned in the excitation zone to produce a discharge thereby generating an atmospheric plasma; c) generating a precursor material aerosol in a separate zone by using an atomiser gas or providing a gaseous precursor material, wherein the precursor material is a compound capable of forming radicals when in contact with an atmospheric plasma and which comprises at least one amine function; d) treating at least a part of the polymer substrate surface provided according to (a) with the atmospheric plasma generated according to (b) and the precursor material aerosol generated according to (c) or the gaseous precursor material provided according to (c) thereby depositing a reaction product of the precursor material at least on a part of the polymer substrate surface.

16. The method according to claim 15, wherein (d) comprises: d.1) treating the polymer substrate surface provided according to (a) with the atmospheric plasma generated according to (b); d.2a) introducing the precursor material aerosol generated according to (c) or the gaseous precursor material provided according to (c) into the atmospheric plasma used in (d.1), thereby forming an atmospheric plasma comprising the precursor material; or d.2b) treating the polymer substrate surface directly after step (d.1) in the “afterglow” with the precursor material aerosol generated according to (c) or with the gaseous precursor material provided according to (c).

17. The method according to claim 15, wherein all steps (a) to (d) take place at near atmospheric pressure, preferably at a pressure in the range of from 0.5 to 1.5 bar, more preferably in the range of from 0.8 to 1.2 bar, more preferably in the range of from 0.9 to 1.1 bar.

18. The method according to claim 15, wherein the precursor material is a com-pound capable of forming radicals when in contact with an atmospheric plasma and which contains at least one amine function selected from the group of primary, secondary, tertiary amines and quarternary ammonium salts, preferably from the group consisting of primary, secondary amines and quarternary ammonium salts, more preferably from the group consisting of primary and secondary amines; or from the group consisting of secondary am-mines and quaternary ammonium salts, preferably quaternary ammonium salts.

19. The method according to claim 15, wherein the precursor material is a compound of general formula (I) ##STR00019## R1 and R2 are independently selected from the group consisting of hydrogen atom, halo-gen atom, CN, CF3, straight or branched alkyl of from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms, a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 6 and y being an integer in the range from 1 to 20, preferably a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 4 and y being an integer in the range from 3 to 18; or a alpha, beta-unsaturated straight or branched alkenyl or alkynyl of 2 to 10 carbon atoms, preferably from 2 to 6 carbon atoms, more preferably from 2 to 4 carbon atoms, C5-C6 cycloalkyl, heterocycloalkyl, C(═Y)XR5, where Y may be S or O, preferably O, and X is O or a bond, R5 is a straight or branched C1-C20 alkyl, a straight or branched C1-C20 alkoxy, a (CH2)x-(CF2)y-CF3 group with x being an integer in the range from 0 to 6 and y being an integer in the range from 1 to 20, preferably R5 is a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 4 and y being an integer in the range from 3 to 18; R3 is selected from the group consisting of hydrogen atom, halogen atom, preferably fluorine or chlorine, C1-C6, preferably C1, alkyl and COOR6, where R6 is a C1-C6 alkyl group; or R1 and R3 may be joined to form a group of the formula (CH2)m, optionally substituted with one or more C1-C4 alkyl group(s), wherein m is an integer in the range of from 2 to 6, preferably 3 or 4; and R4 is a primary or secondary amine group of the general formula (II) ##STR00020## wherein z is selected from the group consisting of —(CH2)p-, wherein p is an integer in the range of from 1 to 10, preferably 1; —(C(═O)—O—(CH2)q-, wherein q is an integer in the range of from 1 to 10, preferably in the range of from 2 to 4, more preferably 2; and —(C6H4)-(CH2)r, wherein r is an integer in the range of from 1 to 10, preferably 1; R4a is a hydrogen atom, an aryl group or a branched or unbranched C1 to C10 alkyl group; R4b is a hydrogen or is selected from the group consisting of a branched or unbranched C1 to C18-alkyl group; a C1 to C6-alkyl-phenyl-R7 group, wherein R7 is a saturated or unsaturated, branched or unbranched C1 to C6-alkyl group; wherein R4a and R4b preferably are both hydrogen atoms, or wherein R4a is preferably a hydrogen atom and R4b is a C2-C5 straight or branched alkyl, more preferable isopropyl or t-butyl, and more preferable tert-butyl.

20. The method according to claim 19, wherein the compound of general formula (I) is selected from the group consisting of allyl amine, t-butylaminoethyl methacrylate (TBAEMA), t-butylaminomethyl methacrylate, t-butylaminopropyl methacrylate, t-butylaminoethyl acrylate, t-butylaminomethyl acrylate, t-butylaminopropyl acrylate, t-butylaminoethyl acrylamide, t-butylaminomethyl acrylamide, t-butylaminopropyl acrylamide, t-butylaminoethyl methacrylamide, t-butylaminomethyl methacrylamid, t-butylaminopropyl methacrylamide, tert-butyl aminomethyl styrene (TBAMS) and poly TBAMS; more preferably from the group consisting of allyl amine, TBAEMA, TBAMS, and poly TBAMS, more preferably allyl amine and TBAEMA., or from the group consisting of tridecafluorooctyl acrylate (TFOA), methacrylic ester of methylpolyethyleneglycol (MPEG 350 MA) and 2-hydroxy-ethyl, methacrylate (HEMA), more preferably TFOA.

21. The method according to claim 15, wherein the precursor material is a solution of the compound of general formula (III) in a solvent ##STR00021## wherein R5, R6, R7 and R8 are independently selected from a group consisting of straight or branched alkyl of from 1 to 20 carbon atoms, preferably from 1 to 18 carbon atoms, preferably R8 is hexyl and R5, R6, R7 are methyl or ethyl; unsubstituted or substituted phenyl, preferably phenyl; benzyl; or wherein R5 and R6 are joined together with N+ to form a six membered ring and R7, R8 are straight or branched alkyl of from 1 to 20 carbon atoms or a bond; wherein X− is selected from the group consisting of a halide, preferably chloride or bromide, sulfonate, sulfate, acetate and carboxylate, preferably acetate; and wherein the solvent is an alcohol, another polar solvent or water; wherein the alcohol or other polar solvent has a logKOW in the range from −3 to +1.

22. The method according to claim 15, wherein the polymer substrate is a homo-polymer or copolymer selected from the group consisting of a thermoset, a thermoplastic, an elastomer and a thermoplastic elastomer, preferably a thermoplastic or a thermoplastic elastomer selected from the group consisting of thermoplastic polyurethane (TPU), poly(ether sulfone) (PESU), polyethylene (PE), polypropylene (PP), cellulose triacetate (TAC), polyamide (PA), polyester (PES), polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polyolefins (PO), polyvinyl chloride (PVC), polystyrene (PS), poly-carbonate (PC), polyketone, poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polyphenylene oxide (PPE), polyacrylate, poly acrylamide, silicone, and any blend of two or more thereof, preferably from the group consisting of TPU, PA, PES, PO, PS, PC, TAC, silicone, and any blend of two or more thereof, more preferably from the group consisting of TPU, PA, silicone, and any blend of two or more thereof, more prefer-ably TPU and/or silicone.

23. A polymer substrate having deposited on its surface a reaction product of a precursor material obtained or obtainable by the method according to claim 15.

24. A polymer having improved antibacterial properties and/or antiviral properties obtained or obtainable by a method comprising: a) providing a polymer substrate having a surface; b) generating a plasma under atmospheric conditions by passing a carrier gas through an excitation zone and by applying high frequency alternating current to an electrode positioned in the excitation zone to produce a dielectrical barrier discharge thereby generating an atmospheric plasma; c) generating a precursor material aerosol in a separate zone or providing a gaseous pre-cursor material, wherein the precursor material is a compound capable of forming radicals when in contact with an atmospheric plasma; d) treating at least a part of the polymer substrate surface provided according to (a) with the atmospheric plasma generated according to (b) and the precursor material aerosol generated according to (c) or the gaseous precursor material provided according to (c) thereby depositing a reaction product of the precursor material at least on a part of the polymer substrate surface.

25. The polymer having improved antibacterial properties and/or antiviral properties according to claim 24, wherein the precursor material is a compound capable of forming radicals when in contact with an atmospheric plasma and which contains at least one amine function selected from the group of primary, secondary, tertiary amines and quarternary ammonium salts, preferably from the group consisting of primary, secondary amines and quarternary ammonium salts, more preferably from the group consisting of primary and secondary amines.

26. The polymer having improved antibacterial properties and/or antiviral properties according to claim 24 wherein the precursor material is a compound of general formula (I) ##STR00022## wherein R1 and R2 are independently selected from the group consisting of hydrogen atom, halo-gen atom, CN, CF3, straight or branched alkyl of from 1 to 20 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably from 1 to 4 carbon atoms, a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 6 and y being an integer in the range from 1 to 20, preferably a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 4 and y being an integer in the range from 3 to 18; or a alpha, beta-unsaturated straight or branched alkenyl or alkynyl of 2 to 10 carbon atoms, preferably from 2 to 6 carbon atoms, more preferably from 2 to 4 carbon atoms, C5-C6 cycloalkyl, heterocycloalkyl, C(═Y)XR5, where Y may be S or O, preferably O, and X is O or a bond, R5 is a straight or branched C1-C20 alkyl, a straight or branched C1-C20 alkoxy, a (CH2)x-(CF2)y-CF3 group with x being an integer in the range from 0 to 6 and y being an integer in the range from 1 to 20, preferably R5 is a (CH2)x-(CF2)y-CF3 group with x being zero or an integer in the range from 1 to 4 and y being an integer in the range from 3 to 18; R3 is selected from the group consisting of hydrogen atom, halogen atom, preferably fluorine or chlorine, C1-C6, preferably C1, alkyl and COOR6, where R6 is a C1-C6 alkyl group; or R1 and R3 may be joined to form a group of the formula (CH2)m, optionally substituted with one or more C1-C4 alkyl group(s), wherein m is an integer in the range of from 2 to 6, preferably 3 or 4; R4 is a primary or secondary amine group of the general formula (II) ##STR00023## wherein z is selected from the group consisting of —(CH2)p-, wherein p is an integer in the range of from 1 to 10, preferably 1; —(C(═O)—O—(CH2)q-, wherein q is an integer in the range of from 1 to 10, preferably in the range of from 2 to 4, more preferably 2; and —(C6H.sub.4)—(CH2)r, wherein r is an integer in the range of from 1 to 10, preferably 1; R4a is a hydrogen atom, an aryl group or a branched or unbranched C1 to C10 alkyl group; R4b is a hydrogen atom or is selected from the group consisting of a branched or unbranched C1 to C18-alkyl group; a C1 to C6-alkyl-phenyl-R7 group, wherein R7 is a saturated or unsaturated, branched or unbranched C1 to C6-alkyl group; wherein R4a and R4b preferably are both hydrogen atoms, or wherein R4a is preferably a hydrogen atom and R4b is a C2-C5 straight or branched alkyl, more preferable isopropyl or t-butyl, and more preferable tert-butyl.

27. The polymer having improved antibacterial properties and/or antiviral properties according to claim 24, wherein the precursor material is a solution of the compound of general formula (III) in a solvent ##STR00024## wherein R5, R6, R7 and R8 are independently selected from a group consisting of straight or branched alkyl of from 1 to 20 carbon atoms, preferably from 1 to 18 carbon atoms, more preferred R8 is hexyl and R5, R6, R7 are methyl or ethyl; unsubstituted or substituted phenyl, preferably phenyl; benzyl; or wherein R5 and R6 are joined together with N+ to form a six membered ring and R7, R8 are straight or branched alkyl of from 1 to 20 carbon atoms or a bond; wherein X− is selected from the group consisting of a halide, preferably chloride or bromide; sulfonate; sulfate; acetate; and carboxylate, preferably acetate; and wherein the solvent is an alcohol, another polar solvent or water, wherein the compound of general formula (III) is preferably selected from the group consisting of hexadecyltrimethylammonium chloride (CTAB), benzalkonium chloride (BAC), hexadecylpyridinium chloride (HDPC), octadecyl dimethyl (3-triethoxysilylpropyl) ammonium chloride and mixtures of two or more of these compounds; wherein the alcohol or other polar solvent has a logKOW in the range from −3 to +1.

28. Use of the polymer having improved antibacterial properties and/or antiviral properties obtained or obtainable by a method comprising: a) providing a polymer substrate having a surface; b) generating a plasma under atmospheric conditions by passing a carrier gas through an excitation zone and by applying high frequency alternating current to an electrode positioned in the excitation zone to produce a dielectrical barrier discharge thereby generating an atmospheric plasma; c) generating a precursor material aerosol in a separate zone or providing a gaseous pre-cursor material, wherein the precursor material is a compound capable of forming radicals when in contact with an atmospheric plasma; d) treating at least a part of the polymer substrate surface provided according to (a) with the atmospheric plasma generated according to (b) and the precursor material aerosol generated according to (c) or the gaseous precursor material provided according to (c) thereby depositing a reaction product of the precursor material at least on a part of the polymer substrate surface; or of the polymer having improved antibacterial properties and/or antiviral properties obtained or obtainable by a method according to claim 15, for medical applications, antibiofouling applications, hygiene applications, food industry applications, industrial or computer related applications, consumer goods applications and appliances, public and public transport applications, underwater, water sanitation or seawater applications.

Description

EXAMPLES

[0231] 1. Chemicals

[0232] 1.1 TPUs

[0233] TPU 1:

[0234] The thermoplastic polyurethane (TPU) used for this example was a polyether grade obtained from the reaction of 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as components of the urethane-rich hard blocks, and polytetrahydrofuran (polyether) macrodiol, with Mn ˜1000 g/mol and polydispersity index of ˜2, as the main component of the soft phase. The hard block content was 22 weight-% and the glass transition temperature was −50° C.

[0235] Extrusion:

[0236] The TPU foils were obtained by an extrusion process with a single screw extruder, diameter=45 mm and a length of 30 D using 3 zone screw with a compression ratio of 1:2,5 and at temperatures between 150° and 205° C. (“length of 30 D” means that the length is 30 times the diameter of the screw, i.e. 135 cm). A slit die is installed at the end of the extruder to obtain the TPU foil. For the tests the thickness was not crucial as long as the foil was continuous (without holes) and thin enough to pass through the electrode gap.

[0237] TPU 2:

[0238] The thermoplastic polyurethane (TPU) used for this example was a polyether grade obtained from the reaction of 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as components of the urethane-rich hard blocks, and polytetrahydrofuran (polyether) macrodiol, with Mn ˜1000 g/mol and polydispersity index of ˜2, as the main component of the soft phase. The hard block content was 22-23 weight-% and the glass transition temperature was −40° C.

[0239] Extrusion and Moulding:

[0240] The TPU plates were obtained by an extrusion/injection molding process with a single screw extruder, diameter=45 mm and a length of 23 D using 3 zone screw with a compression ratio of 1:2,0 and at temperatures between 200° and 225° C. The mold temperature was 35° C.

[0241] 1.2 Precursors for Coating

TBAEMA: t-butylaminoethyl methacrylate
TBAMS: tert-butyl aminomethyl styrene
PTBAMS: Poly tert-butyl aminomethyl styrene
Allylamine: 2-Propen-1-amine
BAC: benzalkonium chloride
HDPC: hexadecylpyridinium chloride
CTAB: hexadecyltrimethylammonium chloride

[0242] 2. Method A (PlasmaZone® technology developed by VITO (Mol, Belgium))

[0243] The plasma treatment was carried out in a direct plasma configuration in a parallel plate DBD (dielectric barrier discharge) plasma installation at atmospheric pressure using a discharge frequency of 1.5 kHz. The dimensions of the two high voltage electrodes are 340×80 mm and the interelectrode distance (gap) of the two electrodes is 2 mm. The upper electrode is mounted on an X-moving table which is moved at a linear speed of 2 m/min. A sheet of the substrate material (TPU according to section 1.1) was placed on the lower grounded electrode. The substrate was submitted to an argon plasma (carrier gas) at a flow of 10 slm (standard 1/min) and at a input power of 100 W. The respective precursor for coating was injected as an aerosol in the plasma zone under an argon flow of 1-2 slm. The treatment time was varied by running multiple passes (10-20). In some cases, a plasma post curing was carried out after the coating deposition (see table).

[0244] 3. Method B (PlasmaLine® Technology Developed by VITO (Mol, Belgium))

[0245] The plasma treatment was carried out in an indirect plasma configuration at atmospheric pressure. The plasma was blown out of the PlasmaLine® (PL200) using a flow of 250 slm nitrogen or argon to form a so-called plasma afterglow of 200 mm in width. The applied power to the system was 150 W in the case of argon and 400 W in case of the nitrogen. A sheet of the substrate (TPU according to section 1.1) was placed 3 mm below the installation. The treatment was carried with a nitrogen or argon flow of 250 slm. The precursor was injected as an aerosol in the plasma afterglow using two atomizers with a flow from the atomizer of 1-2 slm.

[0246] 4. Method C (PlasmaZone® Technology Developed by VITO (Mol, Belgium))

[0247] The plasma treatment was carried out in a direct plasma configuration in a parallel plate DBD (dielectric barrier discharge) plasma installation at atmospheric pressure using a discharge frequency of 1.5 kHz. The dimensions of the two high voltage electrodes were 340×80 mm and the interelectrode distance (gap) of the two electrodes was 3 mm. The upper electrode was mounted on an X-moving table which was moved at a linear speed of 2 m/min. A sheet of the substrate material (TPU according to section 1.1) was placed on the lower grounded electrode. The substrate was submitted to an argon plasma (carrier gas) at a flow of 10 slm (standard 1/min) and at a input power of 70-100 W. The precursor is injected as an aerosol in the plasma zone under an argon flow of 0.8-2 slm. The number of passes was 20.

[0248] 5. Method D (PlasmaZone® Technology Developed by VITO (Mol, Belgium))

[0249] The plasma treatment was carried out in a direct plasma configuration in a parallel plate DBD (dielectric barrier discharge) plasma installation at atmospheric pressure using a discharge frequency of 1.5 kHz. The dimensions of the two high voltage electrodes were 340×80 mm and the interelectrode distance (gap) of the two electrodes was 3 mm. The upper electrode was mounted on an X-moving table which was moved at a linear speed of 2 m/min. A sheet of the substrate material (TPU according to section 1.1) was placed on the lower grounded electrode. The substrate was submitted to an argon plasma (carrier gas) at a flow of 20 slm (standard 1/min) and at a input power of 100 W. The precursor is injected as an aerosol in the plasma zone under an argon flow of 0.8-1.5 slm. The number of passes were between 20-30.

[0250] 6. Contact Angle Measurements

[0251] The contact angle to water (sessile drop method) was measured by applying 10 drops of water of a cut strip of the respective TPU foil. The water droplet volume was 2 microliters, and as water quality nanopure water (18.2 megaohm ionic purity) was used. The contact angle was in each case measured for an untreated (Reference) and for a coated TPU foil.

[0252] 6. Sample Preparation and Measurements

6.1 Examples 1-11

[0253] According to method A, the following examples were run using TPU 1 foils as substrate. Contact angles against water of the treated foils were measured (see table 1 below).

TABLE-US-00001 TABLE 1 Plasma treatment conditions (method A) and contact angles against water Atomiser gas Post Passes Contact angle Example Precursor (slm) curing (nr) against water Reference No plasma treatment 91° 1 TBAEMA 1.5 no 10 7° 2 TBAMS 1.5 no 10 69° 3 TBAMS 1.5 yes 20 28° 4 TBAMS 1.5 no 20 60° 5 TBAMS 1.5 no 24 32° 6 TBAEMA 1.5 no 20 70 7 8 wt % PTBAMS in Me- 2 no 20 43° OH 8 8 wt % PTBAMS in Me- 2 yes 20 31° OH 9 4 wt % PTBAMS in Me- 2 yes 20 28° OH 10 4 wt % PTBAMS in 2 yes 20 30° TBAMS 11 Allylamine 1 no 20 6°

[0254] It was clearly apparent that the CEP treatment of the TPU substrate reduced the contact angle against water at least by 22 i.e. all plasma treated TPU substrates were clearly made more hydrophilic by the plasma deposited coating and had a contact angle <90°, preferably <70°.

6.2 Example 12-19

[0255] According to method B, the following examples were run using TPU 1 foils as substrate. Contact angles against water of the treated foils were measured (see table 2 below).

TABLE-US-00002 TABLE 2 Plasma treatment conditions (method B) and contact angles against water Atomiser gas Contact angle Example Precursor flow (slm) Passes (nr) against water Reference No plasma treatment 91° 12 TBAEMA 1.5 10 10° 13 TBAMS 2 × 1.5 10 68° 14 TBAMS 2 × 1.5 40 68° 15 TBAMS 2 × 1.5 20 68° 16 TBAEMA 2 × 1.5 20 13° 17 TBAEMA 2 × 1.5 20 19° 18 4 wt % PTBAMS in 2 × 2   20 69° TBAMS 19 Allylamine 2 × 1   40 5°

[0256] It was clearly apparent that the CEP treatment of the TPU substrate reduced the contact angle against water at least by 22°, i.e. all plasma treated TPU substrates were clearly made more hydrophilic by the plasma deposited coating and had a contact angle <90°, preferably <70°.

6.3 Example 20-46

[0257] According to method C, the following examples were run using silicone plates (MVQ), 40 Shore, A, thickness 2 mm (supplier Kubo Tech, CH) as substrate. Contact angles against water of the treated foils were measured (see table 3 below).

TABLE-US-00003 TABLE 3 Plasma treatment conditions (method C) and contact angles against water Atomiser Contact angle Examples Precursor gas (slm) Power (W) against water Reference No plasma treatment 113° 20 TBAMS 1.5 100 15° 21 TBAMS 2 100 52° 22 TBAMS 1.5 70 83° 23 TBAMS 1.5 100 24 TBAMS 1.5 100 25 TBAEMA 1.5 100 13° 26 TBAEMA 1.5 70 18° 27 TBAEMA 1.5 100 28 TBAEMA 1.5 70 29 BAC ln methanol (50 wt %) 1.3 100 25° 30 BAC in methanol (50 wt %) 1.3 70 19° 31 BAC in methanol (50 wt %) 1.3 100 32 BAC in methanol (50 wt %) 0.9 100 25° 33 BAC in methanol (50 wt %) 0.9 100 23° 34 BAC in methanol (50 wt %) 0.9 100 35 HDPC in methanol (50 wt %) 1.2 100 25° 36 HDPC in methanol (50 wt %) 1.2 70 19° 37 HDPC in methanol (50 wt %) 0.8 100 25° 38 HDPC in methanol (50 wt %) 0.6 100 23° 39 HDPC in methanol (50 wt %) 1.2 100 40 HDPC in methanol (50 wt %) 0.8 100 41 CTAB in methanol (20 wt %) 0.8 100 25° 42 CTAB in methanol (20 wt %) 0.6 100 43 CTAB in methanol (20 wt %) 1 100 35° 44 CTAB in methanol (20 wt %) 1 100 45 CTAB in methanol (20 wt %) 1 70 25° 46 CTAB in methanol (20 wt %) 1 70

[0258] It was clearly apparent that the CEP treatment of the TPU substrate reduced the contact angle against water at least by 30°, i.e. all plasma treated TPU substrates were clearly made more hydrophilic by the plasma deposited coating and had a contact angle <90°, preferably <85°.

6.4 Examples 47-53

[0259] According to method D, the following examples were run using TPU 2 plates as substrate. Contact angles against water of the treated TPU plates were measured (see table 4 below).

TABLE-US-00004 TABLE 4 Plasma treatment conditions (method D) and contact angles against water Atomiser gas Passes Contact angle Example Precursor flow (slm) (nr) against water Reference No plasma treatment 72° 47 TBAMS 1.5 30 22° 48 TBAEMA 1.5 30 <5° 49 BAC (50% in MeOH) 1.5 30 <5° 50 HDPC (50% in MeOH) 0.8 20 30° 51 HDPC (50% in MeOH) 1.2 20 Not measured 52 CTAB (20% in MeOH) 0.8 30 8° 53 CTAB (20% in MeOH) 1 20 Not measured

[0260] It was clearly apparent that the CEP treatment of the TPU plates reduced the contact angle against water at least by 42°, i.e. all plasma treated TPU plates were clearly made more hydrophilic by the plasma deposited coating and had a contact angle <30.

[0261] 7. Antibacterial Activity

[0262] In accordance with ISO 22196:2011, bacteria were inoculated on the plasma treated surface and then covered with a regular film (HDPE or other), and incubated at 37° C. for 24 hours (table 5) and for 1 hr (table 6, 7 and 8). Afterwards, the recovery rate of the bacteria on the test surface was determined by removing the bacterial cells from the surface under addition of a validated neutralizer (e.g. SCDLP broth). The neutralizer solution was then shortly shaken to ensure complete neutralization. Aliquots of the solution containing removed bacteria were plated on suitable culture media and the number of viable bacteria was counted after appropriate incubation time (24-48 hrs).

[0263] The value of antibacterial activity of each sample was calculated according to the following formula:

R=Log(B/C).

R: Value of antibacterial activity expressed as log-reduction compared to a non-plasma treated reference sample;
B: Average of the number of microorganisms on the samples without antibacterial treatment after incubation for 1 or 24 hours;
C: Average number of microorganisms on the antibacterial surface after incubation for 1 or 24 hours.

[0264] The resulting values of antibacterial activity are shown in Table 5, 6, 7 and Table 8 below.

TABLE-US-00005 TABLE 5 values of antibacterial activity of the CEP treated TPU 1 foil after 24 hours incubation time Escherichia coli Staphylococcus aureus DSM 682 ATCC 6538 Log reduction R Log reduction R Example (Antibacterial activity) (Antibacterial activity) Precursor 4 >5.2 >4.7 TBAMS 6 >5.2 >4.7 TBAEMA 8 >5.2 >4.7 8 wt % PTBAMS in MeOH 10 >5.2 >4.7 4 wt % PTBAMS in TBAMS 11 >5.2 >4.7 Allylamine 15 >5.2 >4.7 TBAMS 16 >5.2 >4.7 TBAEMA 18 >5.2 >4.7 4 wt % PTBAMS in TBAMS 19 >5.2 >4.7 Allylamine

[0265] It was clearly apparent that the CEP treatment, i.e. chemically enhanced plasma treatment of the TPU 1 foil substrate surface, generated a strongly antibacterial activity of the TPU foil surface with log reduction values of at least 4.7 for S. aureus and at least 5.2 for Escherichia coli.

TABLE-US-00006 TABLE 6 Values of antibacterial activity of the CEP treated TPU 2 plates after 1 hour incubation time Escherichia coli Staphylococcus aureus DSM 682 ATCC 6538 Log reduction R Log reduction R Example (Antibacterial activity) (Antibacterial activity) Precursor 47 2.5 3.2 TBAMS 48 1.2 2.9 TBAEMA 49 3.1 3.2 BAC (50% in MeOH) 50 2.3 3.2 HDPC (50% in MeOH) 51 3.1 3.2 HDPC (50% in MeOH) 52 2.3 2.8 CTAB (20% in MeOH) 53 2.4 2.9 CTAB (20% in MeOH)

[0266] It was clearly apparent, that the CEP treatment, i.e. chemically enhanced plasma treatment of the TPU 2 plate substrate surface, generated an antibacterial TPU plate surface having a fast antibacterial activity. Already after 1 hour incubation (contact) time, log reduction values of up to 3.1 for S. aureus and at least 2.9 for Escherichia coli were observed.

[0267] 8. Cleaning Experiments

[0268] 8.1. Cleaning Experiments with Water

[0269] 3×3 cm CEP treated TPU 2 plates were submerged in deionized water for 5 min. The CEP treated surface was then rinsed four times with 5 ml deionized water using a pipette. The values of antibacterial activity after washing experiments of the TPU 2 plates are summarized in Table 7.

TABLE-US-00007 TABLE 7 Values of antibacterial activity of the water rinsed CEP treated TPU 2 plates after 1 hr incubation time. Escherichia coli Staphylococcus aureus DSM 682 ATCC 6538 Example [log cfu*/cm.sup.2] [log cfu*/cm.sup.2] Precursor Reference 4.4 4.4 No plasma treatment Log reduction R Log reduction R (Antibacterial activity) (Antibacterial activity) 54 3.4 3.4 BAC (50% in MeOH) 55 3.4 3.4 HDPC (50% in MeOH) *Number of colony forming units (CFU) per cm.sup.2

[0270] It was clearly apparent, that the fast and high antibacterial activity remains after rinsing the TPU plates with water.

[0271] 8.2. Cleaning with Hypochlorite

[0272] 3×3 cm CEP treated TPU 2 plates were submerged for 30 seconds in a 3% sodium hypochlorite solution. The plates were then submerged in water for 5 me and then rinsed four times with 5 ml deionized water using a pipette. The values of antibacterial activity after hypochlorite cleaning experiments of the TPU 2 plates are summarized in Table 8.

TABLE-US-00008 TABLE 8 Values of antibacterial activity hypochlorite cleaned CEP treated TPU 2 plates after 1 hr incubation time. Escherichia coli Staphylococcus aureus DSM 682 ATCC 6538 Example [log cfu*/cm.sup.2] [log cfu*/cm.sup.2] Precursor Reference 4.3 4.5 No plasma treatment Log reduction R Log reduction R (Antibacterial activity) (Antibacterial activity) 56 >3.6 >3.7 BAC (50% in MeOH) 57 nd >3.9 HDPC (50% in MeOH) *Number of colony forming units (CFU) per cm.sup.2

[0273] It was clearly apparent that the fast and high antibacterial activity remains also after cleaning the TPU plates with a hypochlorite solution.

CITED LITERATURE

[0274] WO 2012/004175 A1 [0275] DE 10 2008 029 681A1 [0276] Piera Bosso, Fiorenza Fanelli, Francesco Fracassi, Plasma Process. Polym. 2016, 13, 217-226 [0277] Alaa Fahmy, Renate Mix, Andreas Schonhals, Jorg Friedrich, Plasma Process. Polym. 2012, 9, 273-284 [0278] A. Kreider et al., Applied Surface Science 2013, 273, 562-569