Cluster for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Electron Microscope Unit, The University of New South Wales, Sydney, NSW 2052, Australia.
Biomacromolecules. 2024 Sep 9;25(9):6135-6145. doi: 10.1021/acs.biomac.4c00815. Epub 2024 Aug 19.
Reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization-induced self-assembly (PISA) was conducted in the presence of poly(methyl methacrylate) (PMMA) stabilizer in ethanol/water mixture (80/20 by volume). Two different systems were explored by utilizing (i) 2-ethylhexyl methacrylate (EHMA) and (ii) -butyl methacrylate (BMA). The morphology transitions of these systems were investigated by varying the polymerization conditions, i.e., the presence of the solvophilic comonomer MMA, the solids content, and the target degree of polymerization (DP). As observed in conventional PISA, the presence of solvophilic comonomer, increase in solids content and target DP promoted the formation of high-order morphology. However, unusual morphology transitions were observed whereby the morphology transformed from high-order morphologies to a mixture of spherical nanoparticles, worms, and vesicles and finally to vesicles with increasing target DP. This unusual evolution may be attributed to the limited solubility of PMMA in the ethanol/water solvent mixture, whereby PMMA is soluble at the polymerization temperature but insoluble at lower temperatures.
在乙醇/水混合物（体积比 80/20）中存在聚甲基丙烯酸甲酯（PMMA）稳定剂的情况下，进行可逆加成-断裂链转移（RAFT）分散聚合诱导自组装（PISA）。通过利用（i）2-乙基己基甲基丙烯酸酯（EHMA）和（ii）-丁基甲基丙烯酸酯（BMA）探索了两种不同的体系。通过改变聚合条件，即存在溶剂化共聚单体 MMA、固含量和目标聚合度（DP），研究了这些体系的形态转变。如在常规 PISA 中观察到的，溶剂化共聚单体的存在、固含量和目标 DP 的增加促进了高阶形态的形成。然而，观察到了异常的形态转变，其中形态从高阶形态转变为球形纳米粒子、蠕虫和囊泡的混合物，最后随着目标 DP 的增加转变为囊泡。这种异常的演变可能归因于 PMMA 在乙醇/水溶剂混合物中的有限溶解度，其中 PMMA 在聚合温度下可溶，但在较低温度下不可溶。
