Langmuir, 33, 13828-13833 (2017).

Ko Matsukawa, Tsukuru Masuda, Youn Soo Kim, Aya M. Akimoto*, and Ryo Yoshida*

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温度応答性バルクゲルの表面近傍領域のみに，密度を系統的に変化させながら温度応答性高分子のグラフト鎖を導入し，表面グラフトゲルを作製しました．グラフト密度がバルクの膨潤/収縮挙動に与える影響について検証したところ，系統的な制御が可能であることが明らかとなりました．表面グラフト手法の利点の一つは，構造設計の容易さです．nmスケールでの任意の構造設計により，系統的な機能制御が達成されます．

We prepared thermoresponsive bulk gels with poly(N-isopropylacrylamide) (PNIPAAm) grafted only in the surface region with various graft densities and investigated the effect of the graft density on the bulk volume change properties. The surface-grafted gels induced the formation of skin layers during the shrinking process in response to a temperature increase, and their permeability strongly depended on the graft density. The graft density also controlled the kinetics of the swelling behavior in response to a temperature decrease. These physical properties were discussed on the basis of Young’s modulus of the surface determined by an atomic force microscopy force curve measurement and the homogeneity of the surface polymer network observed by cryo-scanning electron microscopy. This makes it possible to arbitrarily control the characteristics of gels as open or semiclosed systems, which was uniquely determined by the designs of the surface gel networks.