柔性光子晶体结构生色膜的制备及其光学性质

针对硬质纳米微球所构筑的光子晶体在外力作用下结构易损坏,结构色耐久性差的问题,采用分步法合成内刚外柔型聚苯乙烯/聚(甲基丙烯酸甲酯-丙烯酸丁酯)(PS/P(MMA-BA))纳米微球,然后通过熔融剪切法快速制备柔性光子晶体结构生色膜。结果表明:纳米微球制备中内核交联剂二乙烯苯(DVB)可增加PS内核的交联密度和折光指数,使之与外层产生一定的折光指数差,且可与外层P(MMA-BA)共价连接;外层交联剂甲基丙烯酸烯丙酯(ALMA)可使纳米微球外层形成一定的交联点而提高外层的稳定性;当DVB用量为苯乙烯(St)的12.5%,ALMA用量为MMA与BA总量的0.3%时,光子晶体结构生色膜具有优良光学性质和力学性质,产生的结构色鲜艳明亮,且耐弯折、耐冲洗、耐摩擦;适应此类纳米微球组装的熔融剪切法,能快速大面积制备柔性光子晶体结构生色膜。

Preparation and optical properties of flexible photonic crystal film for structural colors

To solve the problem that photonic crystal(PC)structures constructed by hard nanospheres are easy to be damaged by external forces,resulting in poor durability of the structural colors,polystyrene/poly(methyl methacrylate-butyl acrylate)(PS/P(MMA-BA))nanospheres were synthesized by means of the step-by-step polymerization method,and the flexible PC films with structural colors were fabricated by using the prepared PS/P(MMA-BA)nanospheres as assembly blocks through melt-shear induced self-assembly method.The results show that the core cross-linking agent,divinylbenzene(DVB),is able to increase the cross-linking density and refractive index of PS core,to produce a certain refractive index contrast with the outer layer,and to make the PS core surface have double bonds,covalently bonding with the outer layer of P(MMA-BA).The outer layer cross-linking agent,allyl methacrylate(ALMA),improves the stability of the outer layer by forming some crossing-linking bonds.When DVB is 12.5%of styrene(St)and ALMA is 0.3%of the total amount of MMA and BA,PC film demonstrates excellent optical and mechanical properties.PC structures assembled by the nanospheres exhibit excellent flexibility,brilliant structural colors,and high stability during the bending,washing and rubbing tests.The melt-shear assembly method adapted to the PS/P(MMA-BA)nanospheres can rapidly fabricate large area of flexible PC film with structural colors.