Synthesis and in situ atomic force microscopy characterization of temperature-responsive hydrogels based on poly(2-(dimethylamino)ethyl methacrylate) prepared by atom transfer radical polymerization.
Synthesis and in situ atomic force microscopy characterization of temperature-responsive hydrogels based on poly(2-(dimethylamino)ethyl methacrylate) prepared by atom transfer radical polymerization.
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DOI：
10.1021/la061683k
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发表时间：
2007-01
期刊：
影响因子：
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通讯作者：
Jinyu Huang;Brian C. Cusick;J. Pietrasik;Li Wang;T. Kowalewski;Q. Lin;K. Matyjaszewski
中科院分区：
文献类型：
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作者：
Jinyu Huang;Brian C. Cusick;J. Pietrasik;Li Wang;T. Kowalewski;Q. Lin;K. Matyjaszewski
采用原子转移自由基聚合法合成了不同组成的甲基丙烯酸二甲氨基乙酯（DMAEMA）与甲基丙烯酸二苯甲酮（BPMA）的共聚物。这些共聚物的分子量为Mn约30 000 g/mol，而BPMA含量在2.5至10 mol %之间变化。具有低含量的BPMA（2.5和5mol%）的共聚物在水溶液中在33-36 ℃下表现出急剧的热转变。通过使用光掩模技术对旋涂的聚合物层进行UV处理，将水凝胶固定并图案化在硅晶片上。通过变温原位接触模式原子力显微镜定量研究了图案化聚合物凝胶的温度响应行为，发现存在两个较低的临界溶液温度区域。一个区域在25和30摄氏度之间，对应于水凝胶膜的最顶层，而另一个区域，大约40摄氏度，对应于水凝胶的主体。并行的横向力显微镜测量结果显示，刚刚超过转变温度，散装区域表现出增强的摩擦。
Well-defined copolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzophenone methacrylate (BPMA) with different compositions were synthesized via atom transfer radical polymerization. The molecular weights of these copolymers were Mn approximately 30 000 g/mol, while the BPMA content varied from 2.5 to 10 mol %. The copolymers with a low content of BPMA (2.5 and 5 mol %) exhibited a sharp thermal transition at 33-36 degrees C in aqueous solution. A hydrogel was immobilized and patterned on a silicon wafer via UV treatment of the spin-coated polymer layer using a photomask technique. The thermoresponsive behavior of the patterned polymer gel was quantitatively investigated by variable temperature in situ contact mode atomic force microscopy, which revealed the presence of two lower critical solution temperature regions. One region was between 25 and 30 degrees C, corresponding to the topmost layer of the hydrogel film, and the other region, around 40 degrees C, corresponded to the bulk of the hydrogel. Concurrent lateral force microscopy measurements revealed that, just above the transition temperature, the bulk region exhibited enhanced friction.