One-dimensional photonic crystals prepared by self-assembly of brush block copolymers with broad PDI

Brush block copolymers (BBCPs) with narrow polydispersity index (PDI) have the ability to self-assemble into lamellae phase, which makes them candidates for preparing one-dimensional photonic crystal (1D PC) materials. However, BBCPs with broad PDI were supposed to be difficult in fabrication of well-defined PCs. Herein, by utilizing atom transfer radical polymerization and ring-opening metathesis polymerization, widely dispersed BBCPs with polystyrene and poly(tert-butyl acrylate) as side chains were synthesized. Surprisingly, 1D PC thin films were obtained through controlled evaporation of the dichloromethane solution of BBCPs. The thin films exhibited a maximum peak wavelength of reflectance from 294 to 480 nm with the different main chain length even the PDI of the BBCP was as high as 2.1. And, the reflectance turned broader and broader with an increase in PDI and molecular weight. Wide wavelength PCs reflected from 280 to 620 nm were prepared, which showed great potential in displays.