Critical behavior and volume phase transition of hydrogels in a micro-space

2014 Fiscal Year Final Research Report

• Project/Area Number: 25620171
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Polymer/Textile materials
• Research Institution: Shinshu University
• Principal Investigator: SATO Takaaki 信州大学, 学術研究院繊維学系, 准教授 (20373029)
• Co-Investigator(Renkei-kenkyūsha): SUZUKI Daisuke 信州大学, 学術研究院繊維学系, 准教授 (90547019)
• Research Collaborator: YANASE Keiichi 信州大学, 理工学系研究科 ; AMANO Kenshi 信州大学, 理工学系研究科
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 温度応答高分子 / ゲル微粒子 / 小角広角X線散乱法 / 相関長 / 臨界現象 / フラクタル / 誘電分光 / 疎水性相互作用

Outline of Final Research Achievements

This study aimed at establishing a renovated technique for observation and quantitative evaluation of critical phenomena and volume phase transition that thermos-responsive hydrogels exhibit in an extreme micro-space. We targeted better understanding of their critical behavior, involving universality, its breakage, and the underlying molecular mechanisms. We used small- and wide-angle X-ray scattering, dynamic light scattering, and dielectric relaxation spectroscopy. First, we focused on a coil-to-globule transition of poly N-isopropylacrylamide (pNIPAm) in aqueous media, and gained deeper insights into microscopic correlation between the main chains, solvent deuterium isotope effects, and dehydration behavior. Then, we synthesized a series of microgel particles by crosslinking the thermo-responsive polymers. Using the static and dynamic scattering techniques, we succeeded in grasping the gist of their critical behavior, which was quantitatively different from those of bulk gels.

Free Research Field

化学物理