用聚合物乳液粒子构造纳米孔隙超低反射表面

由于粒子堆积膜的孔隙率有限,用聚合物乳液直接组装的纳米孔隙膜在膜厚和折射率的调节能力方面都受到限制,需要可以单独调控粒子膜孔隙率的手段.将聚甲基丙烯酸甲酯(PMMA)和聚苯乙烯(PS)的二元混合乳液在PMMA基板上旋涂,再用环己烷选择性溶去PS粒子得到了超低反射的纳米孔隙膜.改变混合乳液的组成可以调节多孔膜的空隙率,使多层纳米孔隙膜的有效折射率从1.36降低到1.07;调节旋涂速度和成膜乳液的浓度可以控制孔隙膜的厚度.在优化的条件下,在PMMA基板上制备的孔隙膜在波长585nm处的最低反射率仅0.03%、在450～800nm的可见光谱范围内的平均反射率低于0.4%.以本方法制备的纳米孔隙膜有较好的稳定性,在水中用超声波清洗30min后,膜的低反射性能几乎不变.

Ultra-low reflective surface fabricated with polymer latexes

As the porosity of nanoparticle layers is limited,a method of mediating the porosity is needed for adjusting the thickness and refractive index of nanoporous layers of polymer latex.Nanoporous surfaces with extra-low reflectance on PMMA substrate are prepared by spin-casting the PMMA/PS binary latexes,and then selectively removal of PS particles with cyclohexane.The porosity of the polymer latex layers can be tailored from 1.36 to 1.07 by changing the proportion of PMMA and PS particles.Meanwhile,the thickness of the layers can be controlled by changing the spin speed and the concentration of the polymer latex.The nanoporous polymer layers on PMMA substrate prepared under optimal condition exhibited the minimum reflectance only 0.03% at wavelength 585 nm and the average reflectance low than 0.4% in the spectra region from 450 to 800 nm.The antireflective nanoporous layers fabricated by this method are stable that the antireflective performances do not change after ultrasonification in water for 30 min.