Microgels are commonly synthesized in batch experiments, yielding quantities sufficient to perform characterization experiments for physical property studies. With increasing attention on the application potential of microgels, little attention is yet paid to the questions (a) whether they can be produced continuously on a larger scale, (b) whether synthesis routes can be easily transferred from batch to continuous synthesis, and (c) whether their properties can be precisely controlled as a function of synthesis parameters under continuous flow reaction conditions. We present a new continuous synthesis process of two typical but different microgel systems. Their size, size distribution, and temperature-responsive behavior are compared in depth to those of microgels synthesized using batch processes, and the influence of premixing and surfactant is also investigated. For the surfactant-free poly(N-vinylcaprolactam) and poly(N-isopropylacrylamide) systems, microgels are systematically smaller, while the actual size is depending on the premixing of the reaction solutions. However, by the use of a surfactant, the size difference between batch and continuous preparation diminishes, resulting in equal-sized microgels. Temperature-induced swelling–deswelling of microgels synthesized under continuous flow conditions was similar to that of their analogues synthesized using the batch polymerization process. Additionally, investigation of the internal microgel structure using static light scattering showed no significant changes between microgels prepared under batch and continuous conditions. The work encourages synthesis concepts of sequential chemical conditions in continuous flow reactors to prepare precisely tuned new microgel systems.

中文翻译：

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从分批到连续沉淀聚合热敏性微凝胶

微凝胶通常在批处理实验中合成，产生的量足以进行物理性质研究的表征实验。随着人们对微凝胶的应用潜力的日益关注，对以下问题的关注还很少：（a）是否可以大规模连续生产；（b）合成路线是否易于从批生产转移到连续合成；以及（ c）在连续流动反应条件下，是否可以根据合成参数精确控制其性质。我们提出了两种典型但不同的微凝胶体系的新的连续合成方法。将它们的大小，大小分布和温度响应行为与使用分批工艺合成的微凝胶进行了深度比较，并研究了预混和表面活性剂的影响。对于无表面活性剂的聚（N-乙烯基己内酰胺）和聚（N-异丙基丙烯酰胺）体系中，微凝胶的体积较小，而实际尺寸取决于反应溶液的预混合。然而，通过使用表面活性剂，分批制备和连续制备之间的尺寸差异减小，导致了等尺寸的微凝胶。温度引起的在连续流动条件下合成的微凝胶的溶胀与溶胀与使用分批聚合工艺合成的类似物的溶胀与溶胀相似。另外，使用静态光散射对内部微凝胶结构的研究表明，在分批和连续条件下制备的微凝胶之间没有显着变化。这项工作鼓励了连续流反应器中顺序化学条件的合成概念，以制备经过精确调节的新型微凝胶系统。