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.
摘要：
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)通过可逆加成-断裂链转移(RAFT)聚合合成。双亲水二嵌段共聚物（M100S100）由PMPC和阴离子聚（甲基丙烯酸3-磺丙酯钾盐）（PMPS，S)通过RAFT合成。每个嵌段的聚合度为100。PMPC的电荷被分子内中和。在中性pH下，PCBMA中的电荷也由于其羧基甜菜碱结构而被分子内中和。在酸性条件下,当侧羧基被质子化时，PCBMA表现出聚阳离子行为，形成阳离子叔胺基团。PMPS显示出与pH无关的永久阴离子性质。阳离子M100C100和阴离子M100S100在酸性水溶液中的电荷中和混合物由于静电吸引相互作用而形成水溶性聚离子复合物（PIC）胶束。核心由阳离子PCBMA和阴离子PMPS嵌段组成，PMPC块作为覆盖核心表面的外壳，形成球形核壳PIC胶束。pH高于4时，PCBMA中的侧羧基会发生去质子化，过渡到两性离子状态，从而消除PCBMA中的阳离子电荷。因此,在pH高于4时,PIC胶束由于电荷相互作用的消失而解离。
