微相分离结合氢键复合构筑弹性体

Combining Microphase Separation and Hydrogen-bonding Complexation to Construct Elastomer

通过嵌段聚合物的微相分离和高分子氢键复合,使用聚苯乙烯-b-聚丙烯酸-b-聚苯乙烯(SAS)三嵌段聚合物和聚氧化乙烯(PEO)均聚物构筑了具有多层次结构的弹性体(SA/E).聚丙烯酸(PAA)与PEO形成柔性的氢键复合物(PAA/PEO),刚性的聚苯乙烯(PS)与PAA和PEO不相容而发生微相分离,PS作为交联点连接着柔性的PAA/PEO.与PAA/PEO氢键复合物相比,SA/E弹性体力学性能明显提升,通过控制PS质量分数可调节弹性体的模量和强度等力学性能.SA/E弹性体表现出湿度敏感性.并且弹性体经拉伸训练后可获得一定的取向性,弹性回复率保持在98%以上.本弹性体在湿度传感、柔性器件、医用材料等领域具有潜在应用,为构筑新型弹性体提供思路.

By integrating the microphase separation and hydrogen-bonding complexation,here,triblock copolymer polystyrene-b-poly(acrylic acid)-b-polystyrene(SAS)and homopolymer poly(ethylene oxide)(PEO)were used to construct the elastomer(SA/E)with different hierarchical structures.Poly(acrylic acid)(PAA)and PEO can form flexible and stretchable hydrogen-bonded complex.Polystyrene(PS)is neither compatible with PAA nor PEO,and the microphase separation structure will be formed when SAS is associated with PEO.The vitrified PS domains acted as physical cross-link points for soft PAA/PEO hydrogen-bonding complex domains.Compared with PAA/PEO homopolymer hydrogen-bonding complex,the SA/E elastomer shows higher modulus and strength,while maintain the considerable breaking elongation.By changing the PS molecular weight fraction,the SA/E can assemble to various microphase structures and present different mechanical and elastic properties.In addition,the SA/E shows excellent humidity adaptable behavior.The SA/E has different mechanical strengths at different relative humidity conditions.The moisture absorbed in SA/E can serve as plasticizer to enhance the flexibility of PAA/PEO hydrogen-bonding complex domains.Moreover,by cyclic stretching-releasing training,the elastic recovery ratio of SA/E is significantly improved,up to 98%.The elastomer has potential application in smart sensors,flexible devices,and advanced medical materials.This research also provides new methods and ideas for constructing new elastic materials.