Easy to pattern, chemically resistant 1-dimensional polymer photonics

1-dimensional photonic crystals (PCs) reflect certain wavelengths of light using periodic dielectric layers with mismatched refractive indices. Many polymer and inorganic systems exist for fabricating PCs, but challenges remain to create a PC that is stable under harsh chemical conditions. Furthermore, patterning PCs to provide spatial control of reflected light often requires complex or tedious processing steps. Herein, we demonstrate a relatively simple and scalable approach to fabricate chemically resistant PCs from cheap commercially available materials, poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) and phenolic resin (resol), using dip-coating to tune the λ_max of the PC by adjusting the substrate moving velocity. The layers have a naturally high refractive index contrast (Δn≈0.3) and are able to exhibit high stability when exposed to various organic solvents, acid and base aqueous solutions. Moreover, an easy-to-pattern approach is offered by using a PDMS pad to spatially control the hydrophobicity of PVDF-CTFE and direct the deposition of resol layer. We believe this work provides a facile approach for patterned PCs with tunable reflecting behavior and excellent chemical stability.