Sharp temperature dependency of 2D spreading behavior in amphiphilic block copolymer at the air–water interface
Sharp temperature dependency of 2D spreading behavior in amphiphilic block copolymer at the air–water interface
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DOI：
10.1016/j.colsurfa.2005.10.080
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
Takayuki Uekusa;Shusaku Nagano;T. Seki
中科院分区：
文献类型：
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作者：
Takayuki Uekusa;Shusaku Nagano;T. Seki
本文报道了两亲性嵌段共聚物聚苯乙烯-嵌段-聚（4-乙烯基吡啶）（PS-P4 VP）在空气-水界面上的特征铺展行为。当聚合物从环己烷（PS的θ溶剂和P4 VP的不良溶剂）铺展到空气-水界面上时，在表面压力-面积曲线中观察到意外的急剧温度依赖性变化。相反，当使用非θ溶剂如氯仿时，仅观察到可忽略的温度依赖性。在环己烷溶液中，嵌段共聚物的聚集体尺寸强烈地依赖于溶液温度，如通过动态光散射测量所揭示的。观察到的环己烷的现象应该涉及线圈小球构象转变发生在θ溶剂。据我们所知，这项工作提出了第一个明确的例子，即聚合物在溶液中的聚集状态直接反映到空气-水界面处的二维铺展行为。
We report herein characteristic spreading behavior of amphiphilic block copolymer, polystyrene-block-poly(4-vinyl pyridine) (PS-P4VP) at the air–water interface. When the polymer was spread from cyclohexane, a theta solvent for PS and a poor solvent for P4VP, onto the air–water interface, an unexpected sharp temperature dependent change was observed in the surface pressure–area curves. In contrast, when non-theta solvents such as chloroform were used, only negligible temperature dependency was observed. In the cyclohexane solution, the aggregate size of the block copolymer strongly depends on the solution temperatures as revealed by dynamic light scattering measurements. The phenomena observed for cyclohexane should involve the coil-globule conformational transition taking place in the theta solvent. To our knowledge this work presents the first clear example that the aggregation state of polymers in solution is directly reflected to the two-dimensional spreading behavior at the air–water interface.