A straightforward strategy to synthesize loop-stabilized particles in water via PISA is developed. These particular structures can in theory be obtained through the synthesis of amphiphilic BAB triblock copolymers, starting from a hydrophilic middle block A, which is chain extended in an aqueous PISA process with two hydrophobic external blocks B. For this purpose, symmetrical bifunctional poly(N,N-dimethylacrylamide) macroRAFT agents with a central benzoic acid group and an alkyl chain as the Z group are used in the aqueous dispersion polymerization of diacetone acrylamide. For the first time, stable BAB flower-like particles are formed via PISA in pure water. It is shown that the colloidal stability and the resulting particle morphology (spheres, worms, vesicles) strongly depend on the degree of ionization of the central charge in the stabilizer loop, and thus on the pH at which PISA is performed. Moreover, the influence of the length of the alkyl Z group (dodecyl and butyl alkyl chains) on the colloidal stability is studied.

中文翻译：

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PISA在水中对环稳定的BAB三嵌段共聚物的形貌†

开发了一种通过PISA合成水中环稳定颗粒的简单策略。从理论上讲，这些特殊的结构可以通过两亲性BAB三嵌段共聚物的合成来获得，即从亲水性中间嵌段A开始，该中间嵌段在水性PISA工艺中与两个疏水性外部嵌段B进行扩链。为此，对称的双官能聚（N，ñ二甲基丙烯酰胺）具有中央苯甲酸基和烷基链作为Z基团大分子RAFT剂双丙酮丙烯酰胺的含水分散体聚合中使用。第一次，稳定的BAB花状颗粒通过比萨在纯净水中。结果表明，胶体稳定性和所产生的颗粒形态（球形，蠕虫，小泡）在很大程度上取决于稳定剂环中中心电荷的电离程度，并因此取决于在进行PISA时的pH值。此外，研究了烷基Z基团的长度（十二烷基和丁基烷基链）对胶体稳定性的影响。