新型光驱动形状记忆有序多孔膜的设计及构筑

长期以来,设计和制备微纳米尺寸的有序多孔结构是材料科学领域的重要研究课题。聚合物有序多孔膜因兼具高度规则的孔结构和聚合物的多功能性,在工程技术和科学研究领域受到广泛关注。有序多孔膜的孔隙大小、形状及可重复使用等性质对其功能化和潜在应用具有重要影响。形状记忆特性是一种独特的环境响应特性。形状记忆材料能够记忆初始形状,并且在形变后能够在外界刺激下回复其初始形状。将形状记忆特性引入到有序多孔膜中,可实现多孔膜孔形状、尺寸的有效调控,并提高薄膜的可重复使用性,但由于多孔膜孔结构难以实现均匀形变,形状记忆有序多孔膜鲜有报道。华东理工大学林绍梁课题组在光驱动形状记忆多孔膜的设计和制备方面取得了一些新进展。

Design and Construction of Novel Light-Driven Shape Memory Ordered Porous Films

Shape memory polymers (SMPs) are a class of smart polymers possessing reversible shape changing and recovery capabilities which have been widely implemented in both technological innovations and fundamental researches. Porous films with shape memory capability have significant advantages for applications in separation, tissue-engineering, microelectronics, photonic band gap materials and lithography. However, due to the difficulty for manipulating shape changing of pores by traditional methods, few shape memory porous films have been developed. Recently, Prof. Shaoliang Lin and co-workers at East China University of Science and Technology (ECUST) have presented a well-designed way to light-driven shape memory porous films. In their study, a new design of shape memory porous films by combining in-situ crosslinking approach with directional light-manipulation technique was proposed. Diblock copolymer with potential for SMPs was synthesized and then employed to fabricate honeycomb films by a facile "breath figure" method. Through in-situ crosslinking of solid porous films, a two-phase system with the stable network of crosslinked poly(4-vinylpyridine) blocks and reversible phase of photo-responsive azobenzene-containing blocks was readily fabricated. By subsequent directional light-manipulation, honeycomb round pores could be deterministically converted into rectangular shape, rhombus shape or diminished pores. Due to the cooperation of two phase structures, these reshaped pores could perfectly restore to their original structures upon thermal annealing or UV irradiation. This new design of SMPs could circumvent the predicament of traditional SMPs which were based on mechanical deformation and thermal activation, and thus possessed great advantages in the manufacture of novel shape memory microstructures.