Experimental Formulation of Photonic Crystal Properties for Hierarchically Self-Assembled POSS-Bottlebrush Block Copolymers

Rodlike "POSS-bottlebrush block copolymers" (POSSBBCPs) containing crystalline polyhedral oligomeric silsesquioxane (POSS) pendants in A block and amorphous polymeric grafts in B block were utilized to create one-dimensional (1D) photonic crystals (PCs). 3-(12-(cis-5-Norbornene-exo-2,3-dicarboximido) do decanoylamino)propylheptaisobutyl POSS (NB-A16-POSS, M-A) and exo-5-norbornene-2-carbonyl-end poly(benzyl methacrylate) (NBPBzMA, M-B) were employed in sequential ring-opening metathesis polymerization to afford poly[3-(12-(cis-S-norbornene-exo-2,3-dicarboximido)dodecanoylamino)propylheptaisobutyl POSS]-block-poly(exo-5-norbornene-2-carbonylate-graft-benzyl methacrylate)s, P(NB-A16-POSS)-b-P(NB-g-BzMA)s, with well-modulated block compositions (f(A) = 34, 50, and 67 wt %) and overall degrees of polymerization (DP = 323-939). The P(NB-A16-POSS)-b-P(NB-g-BzMA)s hierarchically self-assembled to form highly ordered 1D PC films with periodic lamellar arrays that can reflect visible light with particular wavelengths. Their reflectance bandwidths, reflectivities, and ranges of peak reflectance wavelnegth (lambda(peak)) were largely dependent on the block composition. The 1D PC films based on lamellar P(NB-A16-POSS)-b-P(NB-g-BzMA)s demonstrated the capability of formaulation of lambda(peak) as linear functions of initial polymerization parameter ([M](0)/[I](0)).