Soluble network polymers based on trifluoropropyl‐substituted open‐cage silsesquioxane: Synthesis, properties, and application for surface modifiers.

Fluorinated completely condensed polyhedral oligomeric silsesquioxanes (F‐CC‐POSSs) are widely utilized as surface modifiers for polymeric materials because of their polyhedral and fluorine‐rich structures, which generate polymers with lower surface energies under molecular‐level control. In contrast, their derivatives, fluorinated incompletely condensed or open‐cage POSSs (F‐IC‐POSSs), have similarly intriguing structures, but their utilization for polymer synthesis remains undeveloped. Herein, fluorinated network polymers were prepared based on a 3,3,3‐trifluoropropyl‐substituted IC‐POSSs via hydrosilylation polymerization with isobutyl‐ and phenyl‐substituted IC‐POSS under optimized conditions. In addition to their good thermal stability and tunable refractive indices, these polymers exhibited solution processability and their casting films showed excellent optical transparency, indicating their potential for constructing fluorinated polymers. Their utilization as surface modifiers was examined by addition to poly(methylmethacrylate) (PMMA) films. Intriguingly, modified PMMA films with 2.0 and 0.5 wt% addition showed similar hydrophobicity and surface energies to the films prepared with only fluorinated network polymers. [ABSTRACT FROM AUTHOR]