Nishizawa Yuichiro, Minato Haruka, Inui Takumi, Uchihashi Takayuki, Suzuki Daisuke
Graduate School of Textile Science & Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
Department of Physics and Structural Biology Research Center, Graduate School of Science, Nagoya University, Furo-cho, Chiksusa-ku, Nagoya, Aichi 464-8602, Japan.
Langmuir. 2021 Jan 12;37(1):151-159. doi: 10.1021/acs.langmuir.0c02654. Epub 2020 Dec 23.
Although techniques to produce uniformly sized hydrogel microspheres (microgels) by aqueous free-radical precipitation polymerization are well established, the details of the polymerization process remain mysterious. In the present study, the structural evolution and thermoresponsiveness of the developing microgels during the polymerization were evaluated by temperature-controlled high-speed atomic force microscopy. This analysis clarified that the swelling properties of the precursor microgels formed in the early stages of the polymerization are quite low due to the high incorporation of cross-linkers and that non-thermoresponsive deca-nanosized spherical domains are already present in the precursor microgels. Furthermore, we succeeded in tracking the formation of nuclei and their growth process, which has never been fully understood, in aqueous solution by real-time observations. These findings will help us to design functional microgels with the desired nanostructures via precipitation polymerization.
尽管通过水相自由基沉淀聚合制备尺寸均匀的水凝胶微球（微凝胶）的技术已相当成熟，但聚合过程的细节仍不明确。在本研究中，通过温度控制的高速原子力显微镜对聚合过程中微凝胶的结构演变和热响应性进行了评估。该分析表明，由于交联剂的高掺入率，聚合早期形成的前体微凝胶的溶胀性能相当低，并且前体微凝胶中已经存在非热响应性的十纳米级球形域。此外，我们通过实时观察成功追踪了水溶液中从未被完全理解的核的形成及其生长过程。这些发现将有助于我们通过沉淀聚合设计具有所需纳米结构的功能性微凝胶。
