研究者業績

遊佐 真一

ユサ シンイチ  (Shin'ichi Yusa)

基本情報

所属
兵庫県立大学 大学院工学研究科 助教授・准教授
学位
博士(理学)(大阪大学)

J-GLOBAL ID
200901059347920447
researchmap会員ID
5000099919

外部リンク

委員歴

 1

論文

 293
  • Misato Hayashi, Rintaro Takahashi, Thi Ngan Vu, Kazuaki Matsumura, Shigeru Yamago, Shin-ichi Yusa
    Polymer Journal 2024年8月16日  
  • Kaito Yokota, Rintaro Takahashi, Vu Thi Ngan, Tomoya Nishimura, Michael Kappl, Syuji Fujii, Shin‐ichi Yusa
    Macromolecular Rapid Communications 2024年8月  
    Abstract A dual zwitterionic diblock copolymer (M100C100) consisting of poly(2‐(methacryloyloxy)ethyl phosphorylcholine) (PMPC, M) and poly(3‐((2‐(methacryloyloxy)ethyl) dimethylammonio) propionate) (PCBMA, C) is synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization. A double hydrophilic diblock copolymer (M100S100) consist of PMPC and anionic poly(3‐sulfopropyl methacrylate potassium salt) (PMPS, S) is synthesized via RAFT. The degrees of polymerization of each block are 100. The charges of PMPC are neutralized intramolecularly. At neutral pH, the charges in PCBMA are also neutralized intramolecularly due to its carboxybetaine structure. Under acidic conditions, PCBMA exhibits polycation behavior as the pendant carboxy groups become protonated, forming cationic tertiary amine groups. PMPS shows permanent anionic nature independent of pH. Charge neutralized mixture of cationic M100C100 and anionic M100S100 in acidic aqueous solution forms water‐soluble polyion complex (PIC) micelle owing to electrostatic attractive interactions. The core is composed of the cationic PCBMA and anionic PMPS blocks, with the PMPC blocks serving as shells that covered the core surface, forming spherical core–shell PIC micelles. Above pH 4 the pendant carboxy groups in PCBMA undergo deprotonation, transitioning to a zwitterionic state, thereby eliminating the cationic charge in PCBMA. Therefore, above pH 4 the PIC micelles are dissociated due to the disappearance of the charge interactions.
  • Takanori Yasui, Anne-Laure Fameau, Hyoungwon Park, Thu Thao Pham, Sabrina Pechmann, Silke Christiansen, Shin-Ichi Yusa, Tomoyasu Hirai, Yoshinobu Nakamura, Syuji Fujii
    Advanced science (Weinheim, Baden-Wurttemberg, Germany) e2404728 2024年6月25日  
    Gas marbles are a new family of particle-stabilized soft dispersed system with a soap bubble-like air-in-water-in-air structure. Herein, stimulus-responsive character is successfully introduced to a gas marble system for the first time using polymer particles carrying a poly(tertiary amine methacrylate) (pKa ≈7) steric stabilizer on their surfaces as a particulate stabilizer. The gas marbles exhibited long-term stability when transferred onto the planar surface of liquid water, provided that the solution pH of the subphase is basic and neutral. In contrast, the use of acidic solutions led to immediate disintegration of the gas marbles, resulting in release of the inner gas. The critical minimum solution pH required for long-term gas marble stability correlates closely with the known pKa value for the poly(tertiary amine methacrylate) stabilizer. It also demonstrates amphibious motions of the gas marbles.
  • Ema Onodera, Sari Usuda, Hodaka Hara, Md Harun-Or-Rashid, Syuji Fujii, Yoshinobu Nakamura, Shin-Ichi Yusa
    Langmuir : the ACS journal of surfaces and colloids 40(22) 11757-11765 2024年6月4日  
    Liquid marbles (LMs) can be prepared by adsorption of hydrophobic particles at the air-liquid interface of a water droplet. LMs have been studied for their application as microreaction vessels. However, their opaqueness poses challenges for internal observation. Liquid plasticines (LPs), akin to LMs, can be prepared by the adsorption of hydrophobic particles with a diameter of 50 nm or less, at the air-liquid interface of a water droplet. Unlike LMs, LPs are transparent, allowing for internal observation, thus presenting promising applications as reactors and culture vessels on a microliter scale. In this study, the surface of silica particles, approximately 20 nm in diameter, was rendered hydrophobic to prepare hydrophobic silica particles (SD0). A small amount of poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) was then grafted onto the surface of SD0, yielding SD1. SD0 particles exhibited consistent hydrophobicity irrespective of the environmental pH atmosphere. Under acidic conditions, SD1 became hydrophilic due to the protonation of pendant tertiary amines in the grafted PDPA chains. However, SD1 alone was unsuitable for LP preparation due to its high surface wettability regardless of atmospheric pH, attributable to the presence of PDPA-grafted chains. Therefore, to prepare pH-responsive LP, SD1 and SD0 were mixed (SD1/SD0 = 3/7). Upon exposure to HCl gas, these LPs ruptured, with the leaked water from the LPs being absorbed by adjacent paper. Moreover, clear LPs, prepared using an aqueous solution containing a water-soluble photoacid generator (PAG), disintegrated upon exposure to light as PAG generated acid, leading to LP breakdown. In summary, pH-responsive LPs, capable of disintegration under acidic conditions and upon light irradiation, were successfully prepared in this study.
  • Yu Tomioka, Ryota Tanaka, Thu Thao Pham, Shin-ichi Yusa, Hiroaki Imoto, Kensuke Naka
    Polymer Journal 2024年3月6日  

MISC

 113

主要な講演・口頭発表等

 72

主要な共同研究・競争的資金等の研究課題

 20