RAFT-mediated polymerization-induced self-assembly (RAFT-PISA) has been undergoing fast development currently, promoting research toward more diverse morphologies and more cutting-edge applications. Herein, we demonstrate a polymerization-pH tailored RAFT-PISA (pH-PISA) process, which can conveniently harvest abundant nano/micro-scale morphologies using popular monomers N,N-dimethylacrylamide (DMAA) and diacetone acrylamide (DAAM). The process proceeded through ordinary RAFT dispersion polymerization in an aqueous medium but under different pH conditions. With the use of pH-sensitive bi-carboxylic acid-capped trithiocarbonate as the chain transfer agent (CTA), it was found that the PISA of propagating amphiphilic ABA triblock copolymers was highly affected by the different ionization of the CTA. When the polymerization pH was adjusted to 2.5, an especially wide spectrum of morphologies was detected, including spheres, worms, lamellae, single or double-head tadpoles, vesicle strings and large spheres with surface protrusions. However, the diversity in morphology gradually declined when the polymerization pH was increased to 6 or 8. Diverse structures with same monomer compositions provide an ideal model to explore the influence of particle morphology on ice recrystallization inhibition (IRI) activities. The variations in mean largest grain sizes (MLGS) and growth rates of a single ice crystal were related to packing parameters (P), bridging the interface geometry of the packing of amphiphilic molecules and ice-controlling activities.

中文翻译：

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聚合-pH 定制的 RAFT 介导的聚合诱导的冰重结晶自组装抑制了研究

RAFT介导的聚合诱导自组装（RAFT-PISA）目前正在快速发展，推动研究朝着更多样化的形态和更前沿的应用方向发展。在此，我们展示了一种聚合-pH 定制的 RAFT-PISA (pH-PISA) 工艺，该工艺可以使用流行的单体 N , N-二甲基丙烯酰胺 (DMAA) 和双丙酮丙烯酰胺 (DAAM) 方便地收获丰富的纳米/微米级形态。该过程通过普通的 RAFT 分散聚合在水性介质中进行，但在不同的 pH 条件下进行。使用pH敏感的二元羧酸封端的三硫代碳酸酯作为链转移剂(CTA)，发现增长的两亲性ABA三嵌段共聚物的PISA很大程度上受到CTA的不同电离度的影响。当聚合pH调节至2.5时，检测到特别广泛的形态，包括球体、蠕虫、片状、单头或双头蝌蚪、囊泡串和具有表面突起的大球体。然而，当聚合pH值增加到6或8时，形态的多样性逐渐下降。具有相同单体组成的多种结构为探索颗粒形态对冰重结晶抑制（IRI）活性的影响提供了理想的模型。平均最大晶粒尺寸（MLGS）和单个冰晶生长速率的变化与堆积参数（ P ）有关，该参数连接了两亲分子堆积的界面几何形状和冰控制活性。