Evolution of a Radical-Triggered Polymerizing High Internal Phase Emulsion into an Open-Cellular Monolith
Evolution of a Radical-Triggered Polymerizing High Internal Phase Emulsion into an Open-Cellular Monolith
复制标题
自由基引发聚合高内相乳液演变为开孔整体材料
DOI：
10.1002/macp.201900216
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发表时间：
2019-08-01
影响因子：
2.5
通讯作者：
Wan, Decheng
中科院分区：
文献类型：
--
作者：
Li, Chenhui;Jin, Ming;Wan, Decheng
高内相乳液(HIPE)中最初离散的细胞在聚合过程中/聚合后通过窗口高度相互连接的时间和方式(PolyHIPE)仍然存在争议。以苯乙烯/二乙烯基苯为油相的油包水HIPE体系是目前研究最广泛的体系之一。在这里，提出了新的证据，在大分子表面活性剂和新仪器的帮助下，聚HIPE的演变。该大分子表面活性剂以支化的聚乙烯亚胺为亲水头部，以聚苯乙烯链为疏水尾部。它可以在很大的剂量范围内稳定HIPE，并导致不同的聚HIPE形态，所有这些都被证明是开放细胞整体柱。在较低的大分子表面活性剂用量下，连接细胞的窗口很稀疏但很大，在开放的环境中可以用3D光学显微镜(3DOM)和2D光热红外(2D PTIR)光谱仪有效地检测到。3DOM检测支持HIPE聚合过程中形成窗口的说法。涉及提取聚合HIPE的预着色水滴的测试也有助于在聚合过程中形成开放的细胞结构。2D PTIR提供了表面一旦被大分子表面活性剂覆盖后相分离的证据，这有利于窗口的发展。
The time and manner by which initially discrete cells in a high internal phase emulsion (HIPE) become highly interconnected by windows during/after polymerization (polyHIPE) remain a controversy. Water-in-oil HIPE with styrene/divinylbenzene as the oil phase is one of the most widely studied systems. Here, new evidence is presented on the evolution of polyHIPE with the aid of a macrosurfactant and new instruments. The macrosurfactant has a branched polyethylenimine as the hydrophilic head and polystyrene chains as the hydrophobic tail. It can stabilize HIPE within a wide range of dosages and lead to different polyHIPE morphologies, all of which are proven to be of open-cellular monolith. At a low macrosurfactant dosage, the windows that interconnect the cells are sparse but large and can be effectively detected with a 3D optical microscope (3DOM) and a 2D photothermal infrared (2D PTIR) spectrometer in an open environment. 3DOM detection supports the claim that windows form during HIPE polymerization. Tests involving the extraction of pre-colored water droplets of the polymerizing HIPE also lend support to the formation of an open-cellular structure during polymerization. 2D PTIR provides evidence on phase separation on the surface once covered by the macrosurfactant, which favors window development.