PS-b-PAA嵌段共聚物修饰的智能表面的制备及其响应行为的研究

利用原子转移自由基聚合(ATRP), 再经水解后得到了嵌段共聚物聚苯乙烯-b-聚丙烯酸(PS-b-PAA), 接枝到硅烷偶联剂γ-(2,3环氧丙氧)丙基三甲氧基硅烷γ-(2,3-glycidoxypropyl)trimethoxysilane, GPS]修饰的Si表面得到了对溶剂具有响应性的智能表面, 并通过凝胶渗透色谱(GPC)、傅立叶变换红外光谱(FTIR)、核磁共振(¹H NMR)和原子力显微镜(AFM)等测试手段对产物进行了表征. 然后, 通过接触角测试研究了所得智能表面对不同溶剂的响应行为. 结果显示, PS-b-PAA接枝表面的润湿性与接枝共聚物的组成及表面处理的溶剂性质有关. 在相同的溶剂处理条件下, 共聚物中PS/PAA比值越小, 表面亲水性越大; 乙醇和碱性溶液处理后的表面呈亲水状态, 甲苯和酸性水溶液处理后的表面又切换到疏水状态, 同时其表面的酸碱响应行为具有非常稳定的可逆性.

Preparation of Smart Surface Grafted by PS-b-PAA Copoly-mer Brush and Its Responsive Behaviors

Block polystyrene-b-poly(acrylic acid) (PS-b-PAA) copolymers were obtained by means of atom transfer radical polymerization (ATRP), and then were covalently grafted to γ-(2,3-glycidoxypropyl)- trimethoxysilane (GPS) modified Si surfaces to obtain the solvent surfaces. GPC, FTIR, ¹H NMR and AFM were used to characterize the samples and surfaces. The sur-face responsive behaviors were investigated by water contact angle (CA) measurements. It shows that the wetting properties of the surfaces were dependent on the compositions of grafted copolymer and the proper-ties of the solvents. The surface modified with the compolymer, which has lower PS/PAA ratio, is more hy-drophilic under the same treatment. Hydrophilic surfaces were obtained after the treatments of ethanol and basic aqueous solution, while toluene and acidic aqueous solution treatments would result in the surface hy-drophobicity. Moreover, the switching behaviors of the surface were also proved to be very stable with the external acid-base stimuli.