Tunable Colloidal Crystalline Arrays Via 1-D Anisotropic Expansion

Tunable colloidal crystal structure is important for photonic or phononic applications. Here we explored the fabrication of colloidal crystal-PDMS polymer composite. By infilling/swelling the composite with PDMS elastomer precursor, followed by thermal curing, we observed the irreversible expansion of colloidal crystal-PDMS composite along with the infilling times. Our characterization further confirmed that such an expansion is anisotropic and occurs only along <111> direction of the colloidal crystal, while the other directions remain unchanged.