Molecular Approach To Understand the Tacticity Effects on the Hydrophilicity of Poly(N-isopropylacrylamide): Solubility of Dimer Model Compounds in Water

作者：Katsumoto Yukiteru^*; Kubosaki Noriyuki; Miyata Tatsuhiko

来源：Journal of Physical Chemistry B, 2010, 114(42): 13312-13318.

DOI：10.1021/jp107442h

Although it has been suggested that the tacticity affects the hydrophilicity of poly(N-isopropylacrylamide) (PNiPA), little is known about the physical background of this phenomenon. In this study, we investigated the solubility of the dimer model compounds (DNiPA). The partition coefficient of DNiPA in the two phases of a water/chloroform mixture has indicated that DNiPA with the racemo configuration (r-DNiPA) is more soluble in water than DNiPA with the meso configuration (m-DNiPA). The difference of the hydration free energy between m- and r-DNiPA is estimated to be 1.2 kJ mol(-1). The molecular mechanics (MM) calculations with the GB/SA model have revealed that r-DNiPA in water is more stable by ca. 1 kJ mol(-1) than m-DNiPA, which is in excellent agreement with the experimental result. The MM calculations have also indicated that the intramolecular interaction of m-DNiPA is stronger than that of r-DNiPA, while r-DNiPA is advantageous in terms of the hydration free energy and conformational entropy.

• 出版日期2010-10-28