Thermal Response of Poly(ethoxyethyl glycidyl ether) Grafted on Gold Surfaces Probed on the Basis of Temperature-Dependent Water Wettability
Thermal Response of Poly(ethoxyethyl glycidyl ether) Grafted on Gold Surfaces Probed on the Basis of Temperature-Dependent Water Wettability
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DOI：
10.1021/la8030446
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发表时间：
2009-03-03
期刊：
影响因子：
3.9
通讯作者：
Watanabe, Masayoshi
中科院分区：
文献类型：
--
作者：
Inoue, Sayaka;Kakikawa, Hiroshi;Watanabe, Masayoshi
两个系列的硫醇改性的聚（乙氧基乙基缩水甘油醚）具有不同的链端基团和分子量（PT-PERGE-SH和Bu-PEEGE-SH），在水环境中进行低临界溶解温度（LCST）型相分离，通过Au-S键接枝到金基板上。所得聚合物系留表面的水润湿性随温度不连续地变化，并且这种润湿性的改变根据环境温度的变化是可逆的。对于所有的聚合物检查，在表面上的转变温度，T-C（表面），在该温度下，在表面润湿性的不连续变化的一半发生，随着数均分子量（M-n）的增加。这种趋势不一定与M-n和T-c（soln）（溶液中的相分离温度）之间的关系一致，从而表明不同的因素有助于确定T-c（surf）和T-c（soln）值。对于这两个系列的温敏聚合物，在表面处的聚合物链的拥挤的增加导致的值的T-C（冲浪）增加，由于在链间的相互作用在最外区域的拴系的聚合物链和链的流动性减少的增加。表面相邻链之间更大的相互作用解释了与T-c（soln）相比，T-c（surf）对M-n的更大依赖性。
Two series of thiol-modified poly(ethoxyethyl glycidyl ether) with different chain-end groups and molecular weights (PT-PERGE-SH and Bu-PEEGE-SH), which undergo lower critical solution temperature (LCST)-type phase separation in an aqueous milieu, are grafted onto gold substrates through Au-S bonding. The water wettability of the resultant polymer-tethered surface discontinuously varies with temperature, and this alteration of wettability is reversible according to the variation in temperature of the environment. For all the polymers examined, the transition temperature on surface, T-c(surf), the temperature at which half the discontinuous change in surface wettability occurs, increases with the number-average molecular weight (M-n). This tendency does not necessarily agree with the relationship between M-n and T-c(soln), the phase separation temperature in solution, thereby suggesting that the different factors contribute toward the determination of die T-c(surf) and T-c(soln) values. For both series of thermoresponsive polymers, the increase in crowding of the polymer chains at the surface causes the value of T-c(surf) to increase due to an increase in the interchain interaction in the outermost region of the tethered polymer chains and reduction in the chain mobility. The greater interactions between neighboring chains at the surface explain the larger dependency of T-c(surf) on M-n as compared to that of T-c(soln).