Role of bound water and hydrophobic interaction in phase transition of poly(N-isopropylacrylamide) aqueous solution
Role of bound water and hydrophobic interaction in phase transition of poly(N-isopropylacrylamide) aqueous solution
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DOI：
10.1021/ma034851d
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发表时间：
2003-12-30
期刊：
影响因子：
5.5
通讯作者：
Cho, K
中科院分区：
文献类型：
--
作者：
Cho, EC;Lee, J;Cho, K
已经提出，聚（N-异丙基丙烯酰胺）（PNiPAM）水溶液的相变由至少两个不同的过程组成：（1）结合水围绕PNiPAM的疏水基团或疏水和亲水基团的重排和（2）PNiPAM链中的疏水基团的疏水缔合或PNiPAM侧链残基之间的残余相互作用。然而，一个单一的吸热峰并没有提供直接的证据，这一建议。利用温度调制差示扫描量热法研究表明，PNiPAM水溶液的相变至少包括两个过程。单个吸热峰被分成吸热峰和放热峰，并且来自这些峰的热量取决于所施加的频率。通过对实验数据的曲线拟合，进一步解释了PNiPAM水溶液的相变机理，并对曲线拟合的结果和局限性进行了讨论。
It has been suggested that the phase transition of the poly(N-isopropylacrylamide) (PNiPAM) aqueous solution consists of at least two different processes: (1) a rearrangement of bound water around either hydrophobic or hydrophobic and hydrophilic group of PNiPAM and (2) a hydrophobic association of the hydrophobic groups in the PNiPAM chains or a residual interaction between the PNiPAM side chain residues. However, a single endothermic peak does not provide direct evidence for this suggestion. This study shows that the phase transition in PNiPAM aqueous solution comprises at least two processes by using temperature modulated differential scanning calorimetry. The single endothermic peak is separated into an endothermic and exothermic peak, and the heats from these peaks depend on the applied frequency. Curve fitting to experimental data interprets the transition mechanism of the PNiPAM aqueous solution in more detail, and the results and the limitation of the curve fitting are discussed.