Fan Xiaoxing, Zhang Shengmiao, Zhu Yun, Chen Jianding
Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology Shanghai 200237 China
RSC Adv. 2018 Mar 13;8(18):10141-10147. doi: 10.1039/c8ra01000e. eCollection 2018 Mar 5.
Macroporous polymers based on high internal phase emulsions (HIPEs) possess tunable porous structures and device shapes, and these characteristics make it possible for it to be applied in many fields. However, such materials also demonstrate undesirable properties, such as their brittleness and chalkiness, due to a great amount of surfactant required (5.0-50.0%, relative to the external phase) to realize the transformation from HIPEs to macroporous polymers (polyHIPEs). Herein, O/W HIPEs stabilized by a small amount (as low as 0.1 wt%, relative to the external phase) of commercial surfactant were prepared by magnetic stirring and subsequently homogenizing, and well-defined polyHIPEs were obtained through frozen UV polymerization of these HIPEs. In this process, the prepared HIPE was squeezed out by an injector and frozen at once, which effectively prevented the coalescence of internal phase. Then a 365 nm UV light was utilized to initiate the polymerization and the temperature was kept at -20 °C in order to avoid the melting of the frozen HIPE. After the polymerization, samples, having a typical polyHIPE structure, were obtained. Besides, the original monomer, surfactant and the oil (internal phase) were respectively replaced, and well-defined polyHIPEs could still be obtained. All the results suggested that frozen UV polymerization of HIPEs was an effective and universal approach to produce polyHIPEs with a low amount of surfactant.
基于高内相乳液（HIPEs）的大孔聚合物具有可调节的多孔结构和器件形状，这些特性使其能够应用于许多领域。然而，由于从HIPEs转变为大孔聚合物（聚HIPEs）需要大量表面活性剂（相对于外相为5.0 - 50.0%），这类材料也表现出一些不良特性，如脆性和白垩状。在此，通过磁力搅拌随后均质化制备了由少量（低至相对于外相0.1 wt%）商业表面活性剂稳定的水包油型HIPEs，然后通过这些HIPEs的冷冻紫外聚合获得了结构明确的聚HIPEs。在这个过程中，将制备好的HIPE用注射器挤出并立即冷冻，这有效地防止了内相的聚结。然后利用365 nm紫外光引发聚合反应，并将温度保持在 -20°C以避免冷冻的HIPE融化。聚合后，获得了具有典型聚HIPE结构的样品。此外，分别替换了原始单体、表面活性剂和油（内相），仍然可以获得结构明确的聚HIPEs。所有结果表明，HIPEs的冷冻紫外聚合是一种有效且通用的方法，可用于制备具有少量表面活性剂的聚HIPEs。
