JPWO2013118736A1 - Surface treatment agent for hydrophobic material and surface treatment method - Google Patents

Abstract

Adsorption treatment on the surface easily and stably using both hydrophobic interaction and electrostatic interaction, which are intermolecular forces acting in an aqueous medium, between the silicon-containing polymer surface and the surface treatment agent Provided is a polymer type surface treatment agent.

Description

The present invention relates to a polymer-type surface treatment agent capable of hydrophilizing the surface of a highly hydrophobic silicon-containing polymer and imparting lubricity, and a surface treatment method using the surface treatment agent.

Silicon-containing polymers represented by polydimethylsiloxane (silicone (registered trademark) rubber) have excellent properties such as water repellency, chemical resistance, thermal stability, flexibility, gas permeability, and optical properties. Therefore, it is widely used not only in industry but also in medicine. However, due to the hydrophobicity resulting from the chemical structure, there are problems such as large irritation to tissues and adsorption of biological components on the surface when applied to medical treatment. Therefore, when a hydrophobic polymer material is used in a living environment, it is necessary to consider the familiarity between the material and the living body, and thus a hydrophilic treatment on the surface is required so that it can be immediately applied in an environment mainly composed of water. ing.

Conventionally, a method of generating a hydrophilic functional group on the surface of a hydrophobic polymer material by a technique such as plasma treatment, glow discharge treatment, or ion etching has been employed (see Non-Patent Documents 1 to 7). However, with these techniques, for example, the surface of a polymer material such as polydimethylsiloxane having high polymer chain mobility (the orientation of the functional group) cannot be stably hydrophilized for a long period of time. (See Non-Patent Documents 8 to 10). That is, in polydimethylsiloxane etc., once generated, the hydrophilic functional group enters the polymer material again over time, so that there is a problem that stable surface hydrophilicity cannot be obtained over a long period of time. Furthermore, in the case of a thin tube-like member such as a catheter or an endoscope, it is difficult to perform plasma treatment on the inner surface.

In addition, as a method for hydrophilizing the surface of a hydrophobic polymer material, chemical modification with a hydrophilic polymer is also performed (see Non-Patent Document 11). However, this method is complicated in operation and is usually a process of surface treatment. Since non-polar organic solvents such as chloroform are used, there are concerns about adverse effects on living bodies. Furthermore, when custom-made devices such as dentures are made using hydrophobic polymer materials, such devices must not be deformed by surface treatment. This method is not suitable, and it is considered that a method based on mild and simple processing conditions is necessary.

Against this background, there is a strong demand for a surface treatment that simply makes the surface hydrophilic and improves the adsorption and lubricity of biological components on the surface.

J. et al. G. Aaluzum, S.M. Young, R.A. D'Souza, L.A. Liu, M.M. A. Book and H.M. D. Sheerdown, Biomaterials 31 (2010) 3471 A. Wu, B.B. Zhao, Z. Dai, J. et al. Qin and B.B. Lin, Lab Chip 6 (2006) 942 Y. Yuan, X. et al. Zang, F.M. Ai, J.A. Zhou, J. et al. Shen and S. Lin, Polym. Int. 53 (2004) 121 S. Pintro, P.M. Alves, C.I. M.M. Matos, A. C. Santos, L.M. R. Rodrigues, J.M. A. Teixeira and M.M. H. Gil, Colloids Surf. B: Biointerfaces 81 (2010) 20 H. Makamba, Y .; Y. Hsieh, W.H. C. Sung, and S.K. H. Chen, Anal. Chem. 77 (2005) 3971 M.M. Farrell and S.M. Beaudoin, Colloids Surf. B: Biointerfaces 81 (2010) 468. H. Chen, Z. Zhang, Y. et al. Chen, M.M. A. Brook and H.C. D. Sheerdown, Biomaterials 26 (2005) 2391 M.M. Ouyang, C.I. Yuan, R.A. J. et al. Muisener, A.M. Boulares, and J.M. T. T. et al. Koverstein, Chem. Mater. 12 (2000) 1591 D. Bodas and C.I. K. Malek, Microelectr. Eng. 83 (2006) 1277 M.M. Morra, E .; Occhiello. R. Marola, F.M. Garbassi, P.A. Humphrey and D.H. Johnson, J.M. Colloid Interface Sci. 137 (1990) 11 Y. Iwasaki, M .; Takamiya, R .; Iwata, S .; Yusa and K. Akiyoshi, Colloids Surf. B: Biointerfaces 57 (2007) 226

Therefore, the problem to be solved by the present invention is efficient and simple, excellent durability, improved wettability of the surface of the silicon-containing polymer, friction characteristics based on this, bio-contamination resistance, etc. An object of the present invention is to provide a polymer-type hydrophilization treatment agent (surface treatment agent) and a hydrophilization treatment method (surface treatment method) that can be improved without changing the structure and physical properties of the silicon-containing polymer.

The present inventor has intensively studied to solve the above problems. As a result, the present inventors have found a polymer-type surface treatment agent and a surface treatment method that can be adsorbed and fixed on a surface from a medium centered on water and stabilized. In other words, between the silicon-containing polymer surface and the polymer-type surface treatment agent, both hydrophobic interaction and electrostatic interaction, which are intermolecular forces acting in an aqueous medium, are effectively used, making it easy and stable. The present inventors have completed the present invention by finding a polymer-type surface treatment agent that can be adsorbed on the surface and conditions under which the surface treatment agent acts effectively.

That is, the present invention is a surface treatment agent for a hydrophobic polymer material, which has a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a tertiary amine in the side chain. The present invention relates to a surface treatment agent comprising a copolymer having a monomer unit.

Moreover, in one aspect | mode, the surface treating agent of this invention further contains the mixed solvent of water and ethanol. Preferably, the content of water in the mixed solvent is 20 to 80 volume percent.

式中、Ｒ^１は、炭素数１〜５の直鎖または分岐鎖のアルキレンを表し、Ｒ^２は、炭素数４〜１５の直鎖または分岐鎖のアルキルを表し、Ｒ^３は、炭素数１〜５の直鎖または分岐鎖のアルキレンを表し、各Ｒ^４は、それぞれ独立に炭素数１〜５の直鎖または分岐鎖のアルキルであり；ｘ、ｙ、及びｚは、互いに独立して、２以上の整数を表し：各モノマーユニットはランダムな順序で結合している。Here, as a copolymer contained in the surface treating agent of this invention, the copolymer which has a structure shown by following formula (1) is mentioned, for example.

In the formula, R ¹ represents a linear or branched alkylene having 1 to 5 carbon atoms, R ² represents a linear or branched alkyl having 4 to 15 carbon atoms, and R ³ represents a carbon number of 1 Represents a linear or branched alkylene of ˜5, each R ⁴ is independently a linear or branched alkyl having 1 to 5 carbon atoms; x, y, and z are independently of each other; Represents an integer greater than or equal to 2: Each monomer unit is linked in a random order.

Preferably, in Formula (1), R ¹ is an ethylene group, R ² is an ethylhexyl group, R ³ is an ethylene group, and each R ⁴ is a methyl group or an ethyl group. Moreover, x / (x + y + z) is 0.15-0.4, y / (x + y + z) is 0.6-0.8, and z / (x + y + z) is 0.05-0.2.

The concentration of the copolymer component in the surface treatment agent of the present invention is preferably 0.2 to 1.5 weight percent.

The hydrophobic polymer material treated with the surface treating agent of the present invention is preferably a silicon-containing polymer, and more preferably polydimethylsiloxane.

In another aspect, the present invention relates to a method for treating a surface of a hydrophobic polymer material, comprising the step of applying the surface treatment agent to the surface of the hydrophobic polymer material. Preferably, the surface treatment method of the present invention does not require a step of plasma treating the surface of the hydrophobic polymer material before the step of applying the surface treatment agent. Moreover, the said method can be a method of hydrophilizing the surface of hydrophobic polymer material.

In a further aspect, the present invention provides a coating film of a copolymer having a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a monomer unit having a tertiary amine in the side chain. On the surface of a hydrophobic polymer material. For example, the present invention relates to a hydrophobic polymer material that has been surface-treated by the above-described surface treatment method.

The hydrophobic polymer material of the present invention is preferably a silicon-containing polymer, more preferably polydimethylsiloxane.

According to the present invention, it is possible to provide a surface treatment agent and a surface treatment method for the surface of a hydrophobic polymer material that are efficient and simple and excellent in durability. Further, the surface treating agent of the present invention can efficiently and easily hydrophilize the surface of various hydrophobic polymer materials. For example, the surface treating agent can be applied to materials having high polymer chain mobility such as polydimethylsiloxane. However, it is extremely useful in that it can stably make the surface hydrophilic over a long period of time.

Since the surface treatment agent of the present invention contains a copolymer having a hydrophobic group and a tertiary amine, the hydrophobic interaction between the copolymer side chain and the surface of the hydrophobic polymer material in a solvent containing water. Both electrostatic interaction and electrostatic interaction can be effectively utilized, thereby achieving the effect that the adsorption of the copolymer on the surface of the hydrophobic polymer material can be stabilized.

Since the surface treatment method of the present invention can coat a hydrophilic copolymer using a mixed solvent of water and ethanol, it is possible to use both the hydrophobic interaction and the electrostatic interaction described above. In addition to improving the adsorption stability, it is not necessary to use a conventionally used nonpolar organic solvent, and adverse effects on living bodies or the environment can be suppressed.

Furthermore, since the surface treatment method of the present invention does not require pretreatment such as conventional plasma treatment, plasma treatment is performed on the inner surface like a thin tube-like member such as a catheter or an endoscope. If it is difficult, or if it should avoid deformation due to surface treatment under severe conditions such as plasma treatment, such as a custom-made device, mild conditions using the surface treatment agent of the present invention The surface treatment is possible, and the surface treatment can be performed according to the physical properties, shape, application, etc. of the hydrophobic polymer material to be treated. .

In other words, by improving the surface characteristics of silicon-containing polymers with excellent material properties, water wettability, frictional characteristics, biological contamination, etc. can be reduced, and the medical field as artificial lungs, contact lenses, catheters, and sensors can be reduced. In addition to expanding the range of applications, new applications such as biochips and microdevices that are difficult to surface-treat in post-processing using excessive conditions because they are manufactured by precision processing can be cultivated.

FIG. 1 is a graph of the maximum wavelength peak of ANS-Na fluorescence in a copolymer solution. FIG. 2 is a graph showing the underwater contact angle on the surface of polydimethylsiloxane. Among the bar graphs, white is a value immediately after the surface treatment, and black is a value after being immersed in water for 1 hour. FIG. 3 is a graph showing the underwater contact angle with respect to the P / Si ratio on the polydimethylsiloxane surface. FIG. 4 is a graph showing the time dependence of the ratio of phosphorus atoms to silicon atoms (P / Si) on the surface of polydimethylsiloxane surface-treated with a PMED solution. FIG. 5 is a graph showing the time dependence of the ratio of phosphorus atoms to silicon atoms (P / Si) on the surface of polydimethylsiloxane surface-treated with a PMEH solution. FIG. 6 is a graph showing the time dependence of the dynamic friction coefficient on the surface of polydimethylsiloxane surface-treated with a PMED solution. FIG. 7 is a schematic diagram showing the adsorption behavior of PMED and PMEH on the polydimethylsiloxane surface.

Hereinafter, embodiments of the present invention will be described. The scope of the present invention is not limited to these descriptions, and other than the following examples, the scope of the present invention can be appropriately changed and implemented without departing from the spirit of the present invention.

1. Surface treatment agent The surface treatment agent for the hydrophobic polymer material of the present invention comprises a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a monomer unit having a tertiary amine in the side chain. It comprises a copolymer having a main component.

(1) The copolymer as a main component of the copolymer surface treatment agent comprises a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a tertiary amine in the side chain. This is a so-called terpolymer (terpolymer). However, it does not exclude having monomer units other than these. In addition, these monomer units each typically have a mode of randomly bonding, but a mode having some regularity and periodicity is also included in the scope of the present invention. For example, a statistical polymer, an alternating polymer, It may be a periodic polymer, a block copolymer, and in some cases, a graft polymer.

In the copolymer, the phosphorylcholine group (PC group) is a polar group having the same structure as the polar group of phospholipid (phosphatidylcholine) which is a main component of the biological membrane. Therefore, by including a phosphorylcholine group in the side chain, the copolymer has hydrophilicity (wetability), specifically, extremely good biocompatibility possessed by the surface of the biological membrane, in particular, non-adsorption of biomolecules. And non-activation properties can be imparted, and non-specific adsorption to various molecules can be effectively suppressed, so that excellent antifouling properties can be imparted to the surface of hydrophobic polymer materials such as hydrophobic polymer materials. Can do. Further, in the copolymer, the hydrophobic group has an adsorptivity to the surface of the hydrophobic polymer material to be treated by hydrophobic interaction, and can improve the stability of the surface coating by the copolymer. it can.

Further, in the copolymer, the tertiary amine has a positive charge when water is contained in the solvent, and therefore, between the surface of the hydrophobic polymer material (especially polydimethylsiloxane) having a negative charge. By the electrostatic interaction, the surface adsorption of the copolymer can be stabilized together with the hydrophobic interaction.

The skeleton site in the monomer unit forming the main chain (skeleton) in the copolymer is not particularly limited as long as it can form a polymer by polymerization reaction with each other. Are preferably, for example, vinyl monomer residues, acetylene monomer residues, ester monomer residues, amide monomer residues, ether monomer residues, and urethane monomer residues. Among these, vinyl monomers are preferred. Residues are more preferred. The vinyl monomer residue is not limited. For example, a methacryloxy group, a methacrylamide group, an acryloxy group, an acrylamide group, a styryloxy group, and a styrylamide group in which the vinyl moiety is addition-polymerized are preferable. Among these, a methacryloxy group, a methacrylamide group, an acryloxy group and an acrylamide group are more preferable, a methacrylamide group and an acrylamide group are more preferable, and a methacrylamide group is particularly preferable. And although the said frame | skeleton site | part can also be the same about each monomer unit and can also each differ independently, the aspect which is all methacrylamide groups is preferable.

Accordingly, specific examples of the monomer having a phosphorylcholine group include, but are not limited to, 2-methacryloyloxyethyl phosphorylcholine, 2-acryloyloxyethyl phosphorylcholine, N- (2-methacrylamide) ethyl phosphorylcholine, 4-methacryloyloxybutylphosphorylcholine, Preferred examples include structural units derived from 6-methacryloyloxyhexyl phosphorylcholine, 10-methacryloyloxydecylsylphosphorylcholine, ω-methacryloyldioxyethylene phosphorylcholine, 4-styryloxybutylphosphorylcholine, and the like. Among these, a structural unit derived from 2-methacryloyloxyethyl phosphorylcholine is particularly preferable. 2-Methacryloyloxyethyl phosphorylcholine can be synthesized by the method described in “Kazuhiko Ishihara, Tomoko Ueda, and Nobuo Nakabayashi, Polymer Journal, 22, 355-360 (1990)”. (Monomer compound) can also be easily synthesized based on this method and conventional methods.

Although the said copolymer is not limited, For example, the polymer which has a structure shown by following formula (1) is mentioned preferably.

In the formula (1), R ¹ is a linear or branched alkylene having 1 to 5 carbon atoms, preferably a linear alkylene having 2 carbon atoms, that is, a monomer having a phosphorylcholine group is 2 -Methacryloyloxyethyl phosphorylcholine is preferred.

R ² is a linear or branched alkyl group having 4 to 15 carbon atoms, preferably a branched alkyl group having 4 to 10 carbon atoms, and more preferably a branched alkyl group having 8 carbon atoms. It is. The most preferred alkyl is an ethylhexyl group, that is, the monomer having a hydrophobic group is preferably 2-ethylhexyl methacrylate.

R ³ is a linear or branched alkylene having 1 to 5 carbon atoms, preferably a linear alkylene having 2 to 4 carbon atoms, and more preferably an ethylene group. In addition, each R ⁴ is independently a linear or branched alkyl having 1 to 5 carbon atoms, preferably each R ⁴ is a methyl group or an ethyl group, and most preferably both are methyl groups. It is. That is, the most preferred monomer having a tertiary amine is 2- (N, N-dimethylamino) ethyl methacrylate.

x, y, and z each independently represent an integer of 2 or more. Here, the value of x / (x + y + z) is preferably 0.15 to 0.4, more preferably 0.2 to 0. .35, most preferably 0.2-0.3. If the value exceeds 0.4, it is solubilized only in water, so that the surface adsorptivity to the hydrophobic polymer material is decreased, which is not preferable. Moreover, the value of y / (x + y + z) is preferably 0.6 to 0.8, and more preferably 0.6 to 0.65 from the viewpoint of ensuring appropriate hydrophobicity of the polymer. The value of z / (x + y + z) is preferably 0.05 to 0.2, and more preferably 0.05 to 0.10.

Although the weight average molecular weight (Mw) of the copolymer used by the surface treating agent of this invention is not limited, For example, 5,000-1,000,000 are preferable, More preferably, it is 10,000-300,000. It is.

As described above, the copolymer used in the surface treatment agent of the invention may contain a structural unit derived from another monomer, if necessary, and is not limited, but is usually a structure derived from another monomer. The proportion of units is preferably 30 mol% or less, more preferably 10 mol% or less, based on all structural units constituting the polymer.

In addition, about the synthesis | combination of the said copolymer, preparation of a monomer compound and those polymerization can be fundamentally performed by a conventional method based on a technical level of those skilled in the art.

(2) Surface treatment agent As described above, the surface treatment agent for a hydrophobic polymer material of the present invention contains the above-mentioned copolymer as a main component, and can hydrophilize the surface of the hydrophobic polymer material. It is. The surface treatment agent of the present invention may contain any other component that is generally used as a component of the surface treatment agent of the base material in addition to the copolymer, and is not limited.

As the solvent, a mixed solvent of water and ethanol is preferable, and the content of water in the mixed solvent is preferably 20 to 80 volume percent, more preferably 20 to 50 volume percent. When the solvent is water alone, the copolymer is insoluble, while when the water is 20 volume percent or less, the adsorption stability of the copolymer on the surface of the hydrophobic polymer material is decreased.

The surface treatment agent of the present invention is usually preferably in the form of a solution, and the concentration of the copolymer contained as a main component is preferably, for example, 0.2 to 1.5 weight percent, more preferably 0.5 to 1.25 weight percent, more preferably 0.75 to 1.0 weight percent. When the concentration exceeds 1.5 weight percent, the association of the copolymer becomes remarkable in the solution, which is not preferable.

Although it does not limit as a hydrophobic polymer material used as the object of the surface treating agent of this invention, For example, various hydrophobic polymer materials etc. are mentioned preferably. Examples of the hydrophobic polymer material include acrylic polymers such as polymethyl methacrylate (methacrylic resin; PMMA) and silicon-substituted methacrylic acid ester polymers; various silicone rubbers such as polydimethylsiloxane (including substituted silicone and modified silicone) A material made of an organic material such as polystyrene, polyethylene terephthalate, polycarbonate and polyolefin; a metal, ceramics or glass-based substrate surface-treated with a silane coupling agent. A silicon-containing polymer is preferable, and polydimethylsiloxane is more preferable.

The shape of the hydrophobic polymer material is not particularly limited. For example, in addition to a film shape, a plate shape, a bead shape, a fiber shape, and a hollow tubular shape, holes and grooves provided in a plate-like substrate are also included. Can be mentioned.
Further, the use of the substrate is not limited, but examples thereof include dental materials, dental instruments, various medical devices, contact lenses, artificial organs, biochips, biosensors, oxygen-enriched membranes, and cell storage instruments. It is done. As the dental material, for example, dental prostheses such as plate dentures, bridge dentures, implant dentures, and crowns are preferably mentioned.

2. Surface treatment method (1) Surface treatment method The surface treatment method of the present invention is a method of hydrophilizing the surface of a hydrophobic polymer material as a target substrate. Specifically, the surface treatment agent of the present invention described above is applied to the surface treatment agent of the present invention. It is a method including a step of applying a copolymer to the surface of a substrate by dipping or the like. The coating step may be performed using a surface treatment agent containing the copolymer, which is a photoreactive polymer, as a main component, and is not limited. The hydrophobic polymer material that is the target substrate of the surface treatment method of the present invention is not limited, but examples of the type, shape, and use thereof are the same as those listed in the above section 1. (2). it can.

(2) Hydrophobic polymer material having excellent antifouling property The hydrophobic polymer material of the present invention is a base material whose surface is coated with the above-mentioned copolymer, and the surface is hydrophilized, thus preventing the hydrophobic polymer material. It has excellent soiling properties. Specifically, the hydrophobic polymer material of the present invention is stabilized by adsorbing the hydrophobic group and the tertiary amine in the copolymer to the surface by both hydrophobic interaction and electrostatic interaction, respectively. Since the surface coating is applied, the antifouling property due to surface hydrophilization can be maintained for a long time.
The hydrophobic polymer material of the present invention can be obtained by surface-treating the hydrophobic polymer material by the surface treatment method of the present invention described above. The hydrophobic polymer material of the present invention is not limited, but examples of the type, shape, use and the like are the same as those listed in the above section 1. (2).

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these.

1. The monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) was described in “Method of synthesis by Kazuhiko Ishihara, Tomoko Ueda, and Nobu Nakabayashi, Polymer Journal, 22, 355-360 (1990)” as described above. Commercially available 2-ethylhexyl methacrylate (EHMA), butyl methacrylate (BMA), and 2- (N, N-dimethylamino) ethyl methacrylate (DMAEMA) were used (Tokyo Chemical Industry).

2. Synthesis of MPC-EHMA-DMAEMA Copolymer Under the condition that MPC: EHMA: DMAEMA has a molar ratio of 30:60:10, 2,2′-azobisisobutyronitrile (AIBN) was used as a polymerization initiator. MPC-EHMA-DMAEMA copolymer (PMED) was synthesized in ethanol by a radical polymerization reaction conventionally used in the art. After completion of the reaction, an excess amount of ether: chloroform = 8: 2 solvent was poured, the resulting polymer was purified, and the precipitated polymer was crushed and washed with water for 2 hours to remove unreacted monomers. . Thereafter, the polymer was filtered and freeze-dried. The yield was 33%. The chemical structure of the obtained polymer was identified by H ¹ -NMR (in CD ₃ CD ₂ OD), and the molecular weight was measured by gel permeation chromatography (JASCO). As a result, PMED was a copolymer having a monomer composition ratio of MPC: EHMA: DMAEMA = 26: 64: 10, and the weight average molecular weight was 2.3 × 10 ⁵ . The structure of the obtained PMED (Example 1) is shown below.

  Similar to the PMED of Example 1, various PMEDs were synthesized by changing the addition amount of the polymerization initiator under the condition that the molar ratio of MPC: EHMA: DMAEMA monomer was 30:60:10. As a result, PMEDs having different monomer composition ratios and weight average molecular weights in the copolymer were obtained (Examples 2 to 4). Further, PMED was synthesized by the same procedure with MPC: EHMA: DMAEMA monomer molar ratios of 20:70:10 (Example 5) and 35:60:15 (Example 6). Further, a copolymer PMBD was synthesized in the same manner except that BMA was used instead of EHMA (Example 7). Table 1 shows the monomer composition ratio and the weight average molecular weight of the obtained copolymers of Examples 2 to 7.

3. Preparation of polydimethylsiloxane (PDMS) Liquid PDMS (product name: Silpot 184 (registered trademark), Toray Dow Corning Co., Ltd.) and a curing agent were mixed at 10: 1 (v / v), and the curing reaction was performed at 60 ° C. It went for 4 hours. The resulting mixture was placed under reduced pressure to remove bubbles and obtain a PDMS substrate.

4). Coating of substrate surface In this example, PDMS was used as a hydrophobic polymer material to be treated. The PMED polymer was dissolved in a predetermined ratio ethanol: water mixed solvent to obtain polymer solutions having water contents of 0, 20, 50, and 80 v / v%, respectively. Each polymer concentration was adjusted to 1.0 wt%. The PDMS substrate was previously washed with ethanol. The PDMS substrate was immersed in the PMED solution 5 times for several seconds and then dried. This process was repeated twice, and the substrate was dried under reduced pressure.

As a comparative example, an MPC-EHMA copolymer (PMEH) containing no DMAEMA unit was synthesized in the same manner as described above. The monomer composition ratio of PMEH was MPC: EHMA = 33: 67, and the weight average molecular weight was 1.2 × 10 ⁵ . Using this, a polymer solution of water: ethanol mixed solvent having a water content of 0, 20, 50, 80 v / v% was prepared in the same manner as described above, and the surface treatment of the PDMS substrate was performed under the same conditions. . The structure of PMEH is shown below.

5. Behavior of PMED and PMEH in water-ethanol mixed solvent Using ANS-Na as a fluorescent probe, the dissolution state of PMED (Example 1) and PMEH in the mixed solvent was evaluated. The polymer concentration is 1 wt%, and the concentration of ANS-Na is 1.0 × 10 ⁻⁵ M. The internal polarity in polymer aggregation was calculated using the maximum wavelength of fluorescence of ANS-Na (excitation wavelength: 350 nm). It is known that the maximum wavelength blue shifts to the short wavelength side as it becomes a hydrophobic environment. The results are shown in FIG. When water is 50 and 80 v / v%, it can be seen that the maximum wavelength of both PMED and PMEH is blue-shifted to the short wavelength side compared to the solvent. This result shows that the polymer condenses as the ratio of water in the mixed solvent increases. In particular, at 80 v / v%, it was found that the internal polarity of the polymer condensation was approximately equal to the polarity of the ethanol solvent alone.

6). Evaluation of surface hydrophilicity by measuring the contact angle in water The surface hydrophilicity in water was evaluated by measuring the contact angle in water. This contact angle measurement was performed by bringing bubbles into contact with the surface of the PDMS substrate in water and measuring the contact angle of the bubbles (capable bubble method). The measurement was performed using a static contact angle meter (product name: CA-W, manufactured by Kyowa Interface Science Co., Ltd.) with 2 μL of bubbles in contact with the surface in water at room temperature and normal pressure, and the contact angle was measured. For the measurement, a PDMS substrate cut to a size of 10 × 20 × 0.70 mm ³ was used. The substrates treated with PMED and PMEH were each immersed in water for 1 hour, 24 hours, 72 hours, 120 hours, and 168 hours, and the stability of the copolymer layers was compared.

The results obtained for PMED (Example 1) are shown in FIG. Here, “PMED-0” is obtained by coating a PDMS substrate with a PMED solution of water: ethanol = 0: 100 (that is, ethanol 100% solution), and “PMED-20” is a PDMS substrate that is water-treated. : It means what was coated with a PMED solution of ethanol = 20: 80. The same applies to PMEH. In addition, the smaller the angle, the higher the hydrophilicity of the substrate surface.

From FIG. 2, it can be seen that the PDMS substrate that has been surface-treated with PMED and PMEH has a greatly reduced contact angle, that is, hydrophilicity, compared to the case where it has not been treated. However, when treated with a 100% ethanol solution (PMED-0, PMEH-0), it is almost the same as the untreated case, which means that the copolymer is not sufficiently adsorbed on the substrate surface. Is shown. Here, PMED-20, 50, and 80 showed a small contact angle even after being immersed in water for 1 hour, and the hydrophilicity of the surface was maintained. For PMEH 20, 50, 80, the contact angle increased after immersion in water (particularly for PMEH-80, increased from 0 ° to 70 °). This result shows that PMEH is adsorbed with a weak interaction with the PDMS substrate, and thus easily peeled off when immersed in water. On the other hand, in PMED, it is considered that the amine group in the side chain has a positive charge, thereby more strongly interacting with the surface of the PDMS substrate.

For various PMEDs (Examples 2 to 6) and PMBD (Example 7), similarly to the case of the PMED (Example 1), the contact angle was measured, and the obtained results are shown in Table 1.

7). Stability of PMED and PMEH on PDMS surface The elemental composition on the PDMS surface was analyzed by X-ray photoelectron spectroscopy (AXIS-His 165 Kratos / Shimadzu Corporation). FIG. 3 shows the contact angle with respect to the abundance ratio of phosphorus (P) atoms and silicon (Si) atoms on the PDMS surface. Here, the contact angle uses a value after a PDMS substrate surface-treated with a polymer is immersed in water for 1 hour. Since the phosphorus atom is an element contained only in the phosphorylcholine group of the MPC unit in the polymer, the presence of the coating film can be evaluated by the P / Si ratio. From the results shown in FIG. 3, when the solvent was 100% ethanol (PMED-0, PMEH-0), the presence of P atoms was not observed. It can be seen that no polymer is present. Further, the contact angle decreases as the P / Si ratio increases. This suggests that the PDMS surface is hydrophilized and is attributed to the hydrophilic phosphorylcholine group.

Furthermore, similarly, the time dependency of the P / Si ratio on the PDMS surface was measured by X-ray photoelectron spectroscopy. The results are shown in FIGS. In FIG. 4, in the case of PMED-50 and 80, the P / Si ratio decreased from 0.25 to 0.10 after being immersed in water for 24 hours, whereas in the case of PMED-20, 0 .25. Furthermore, with PMED-20, 50, and 80, a P / Si ratio of about 0.05 was maintained even after immersion for 168 hours.

Here, regarding the relationship between the P / Si ratio of the PDMS surface and the adsorption of fibrinogen, when the surface has a P / Si ratio of 0.035, about 75% of the fibrinogen is compared with the untreated PDMS surface. It has been reported that the amount of surface adsorption decreases (K. Ishihara, B. Ando and M. Takai, Nanobiotechnol. 3 (2007) 83). Based on this, it is suggested that the PMED-treated surface has excellent biofouling resistance even after being immersed in water for 168 hours.

On the other hand, PMEH-20 and 50 have a P / Si ratio reduced from 0.25 to 0.05 or less by immersion in water for 24 hours, and PMEH-80 has an approximately 0. There was a dramatic decrease from 15 to 0.05. In either case, the P / Si ratio was almost 0 after 72 hours of immersion.

From these results, PMED has an amine in the side chain, and when water is contained in the solvent, it is protonated and has a positive charge, so it is more strongly adsorbed on the PDMS surface than PMEH. It is considered a thing. In addition, it is known that the DMAKa polymer has a pKa of about 8.0, and in the case of pH 5.6, 90% of the dimethylamino group is protonated and has a positive charge.

8). Evaluation of lubricity of the surface of PMED treatment The lubricity of the surface of PDMS surface-treated with PMED was evaluated by the dynamic friction coefficient. Using a surface property measuring machine (Heidon Type 32, Shinto Kagaku), the dynamic friction coefficient between the Co—Cr ball and the PDMS surface was measured. A PDMS substrate was formed into a 65 × 35 × 3.0 mm ³ rectangle, and a friction test was performed at room temperature, a load of 0.98 N, and pure water at a maximum of 1.0 × 10 ³ cycles. Each sample was performed three times, and the average value was obtained.

FIG. 6 shows the time dependency of the obtained friction coefficient. Untreated PDMS and PMED-0 (no polymer adsorbed) showed a very high coefficient of friction of about 1.16. On the other hand, when surface treatment was performed with PMED-20, 50, and 80, the friction coefficients showed dramatic decreases of 0.030, 0.030, and 0.015, respectively. From this result, it is considered that the surface treatment with hydrophilic PMED removes the strong hydrophobic interaction, forms a lubricating layer mainly composed of water, and reduces the frictional force. The result is consistent with the result of the above contact angle measurement. Furthermore, it can be said that the fact that the low coefficient of friction was maintained after 1.0 × 10 ³ cycles demonstrates the stability of the PMED layer formed on the surface of the PDMS substrate.

FIG. 7 schematically shows the adsorption behavior of PMED and PMEH on the PDMS surface based on the above experimental results. PMED has a positive charge in aqueous solvents due to the inclusion of DMAEMA, while the PDMS surface is negatively charged, which is why the PMED layer has a very high stability compared to the PMEH layer. Conceivable. That is, the difference in stability between PMEH and PMED is not only due to hydrophobic interaction but also due to binding to the PDMS surface by electrostatic interaction. This results in a stable bond at the PDMS surface with the copolymer involved.

Claims (16)

A surface treatment agent for a hydrophobic polymer material comprising a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a monomer unit having a tertiary amine in the side chain A surface treatment agent comprising a coalescence. The surface treating agent according to claim 1, further comprising a mixed solvent of water and ethanol. The surface treating agent according to claim 2, wherein the content of water in the mixed solvent is 20 to 80 volume percent. The surface treating agent according to any one of claims 1 to 3, wherein the copolymer is a copolymer having a structure represented by the following formula (1).

(Here, R ¹ represents a linear or branched alkylene having 1 to 5 carbon atoms, R ² represents a linear or branched alkyl having 4 to 15 carbon atoms, and R ³ represents a carbon number. 1 to 5 linear or branched alkylene, each R ⁴ is independently a linear or branched alkyl having 1 to 5 carbon atoms; x, y, and z are independently of each other Represents an integer of 2 or more: each monomer unit is bonded in a random order.) The surface treating agent according to claim 4, wherein R ¹ is an ethylene group, R ² is an ethylhexyl group, R ³ is an ethylene group, and each R ⁴ is a methyl group. x / (x + y + z) is 0.15-0.4, y / (x + y + z) is 0.6-0.8, and z / (x + y + z) is 0.05-0.2. The surface treatment agent according to 4 or 5. The surface treating agent according to any one of claims 1 to 6, wherein the concentration of the copolymer component in the surface treating agent is 0.2 to 1.5 weight percent. The surface treating agent according to any one of claims 1 to 7, wherein the hydrophobic polymer material is a silicon-containing polymer. The surface treating agent according to claim 1, wherein the hydrophobic polymer material is polydimethylsiloxane. The surface treatment method of hydrophobic polymer material including the process of apply | coating the surface treating agent of any one of Claims 1-9 to the surface of hydrophobic polymer material. The method according to claim 10, wherein the step of plasma-treating the surface of the hydrophobic polymer material is not required before the step of applying the surface treatment agent. The method of any one of Claims 9-11 which is a method of hydrophilizing the surface of hydrophobic polymer material. A hydrophobic polymer material which has been surface-treated by the method according to claim 9. Hydrophobic polymer material having on its surface a coating film of a copolymer having a monomer unit having a phosphorylcholine group in the side chain, a monomer unit having a hydrophobic group in the side chain, and a monomer unit having a tertiary amine in the side chain . 15. A material according to claim 14, which is a silicon-containing polymer. The material according to claim 15, which is polydimethylsiloxane.

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