Title: High-scattering porous polymer structures and their applications

Abstract

High-scattering media have been widely used in numerous scenarios, including optoelectronic devices, daytime passive radiative cooling, wall paintings and so on. It is well noted that TiO2-nanoparticles-based nanocomposite is the most common recipe for high scattering media by virtue of the high refractive index of TiO2 (~2.6). Recent development has shown that porous polymer structures have the potential to serve as excellent alternatives to conventional TiO2 nanoparticles. However, the intrinsic low refractive index of polymers (~1.5) leads to the insignificant scattering efficiency of porous polymer structures, thereby hindering their further applications. To solve this challenging issue, our group has conducted several works to fabricate high-scattering porous polymer structures by taking inspiration from nature (e.g., Cyphochilus). In this talk, I am going to present the recent progress of our group on the fabrication of high-scattering porous polymer structures and their applications. In detail, several facile and industrially available techniques including supercritical CO2 microcellular foaming and polymerization-induced phase separation are adopted to enable the ultimate fabrication. By well tailoring the fabrication parameters, porous polymer structures with brilliant whiteness can be achieved, which have been successfully applied onto light-emitting diodes and quantum dots films for light enhancement and daytime passive radiative cooling. In addition, we also fabricate optical diffusers with combined high-transmittance and high-haze by utilizing post encapsulation techniques. Overall, porous polymer structures are strong candidates as efficient scatterers due to their abundance and facile and cost-effective fabrication.