Yokota Kaito, Takahashi Rintaro, Ngan Vu Thi, Nishimura Tomoya, Kappl Michael, Fujii Syuji, Yusa Shin-Ichi
Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan.
Department of Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan.
Macromol Rapid Commun. 2024 Dec;45(24):e2400532. doi: 10.1002/marc.202400532. Epub 2024 Aug 1.
A dual zwitterionic diblock copolymer (MC) 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 (MS) 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 MC and anionic MS 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.
通过可逆加成-断裂链转移（RAFT）聚合反应合成了一种由聚（2-（甲基丙烯酰氧基）乙基磷酰胆碱）（PMPC，M）和聚（3-（（2-（甲基丙烯酰氧基）乙基）二甲基铵）丙酸酯）（PCBMA，C）组成的双两性离子二嵌段共聚物（MC）。通过RAFT合成了一种由PMPC和阴离子型聚（甲基丙烯酸3-磺丙酯钾盐）（PMPS，S）组成的双亲水二嵌段共聚物（MS）。每个嵌段的聚合度为100。PMPC的电荷在分子内被中和。在中性pH值下，由于其羧酸甜菜碱结构，PCBMA中的电荷也在分子内被中和。在酸性条件下，随着侧链羧基质子化，形成阳离子叔胺基团，PCBMA表现出聚阳离子行为。PMPS表现出与pH无关的永久性阴离子性质。由于静电吸引相互作用，酸性水溶液中阳离子型MC和阴离子型MS的电荷中和混合物形成水溶性聚离子复合物（PIC）胶束。核心由阳离子型PCBMA和阴离子型PMPS嵌段组成，PMPC嵌段作为覆盖核心表面的壳，形成球形核壳PIC胶束。在pH值高于4时，PCBMA中的侧链羧基发生去质子化，转变为两性离子状态，从而消除了PCBMA中的阳离子电荷。因此，在pH值高于4时，由于电荷相互作用的消失，PIC胶束解离。
