Laser ablation of block copolymers with hydrogen-bonded azobenzene derivatives

Abstract

Abstract Supramolecular assemblies (PS-b-P4VP (AzoR)) are fabricated by hydrogen-bonding azobenzene derivatives (AzoR) to poly(4-vinyl pyridine) blocks of polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP). PS-b-P4VP(AzoR) forms phase separated nanostructures with a period of ∼75–105 nm. A second length scale structure with a period of 2 μm is fabricated on phase separated PS-b-P4VP(AzoR) by laser interference ablation. Both the concentration and the substituent of AzoR in PS-b-P4VP(AzoR) affect the laser ablation process. The laser ablation threshold of PS-b-P4VP(AzoR) decreases as the concentration of AzoR increases. In PS-b-P4VP(AzoR) with different substituents (R = CN, H, and CH3), ablation thresholds follow the trend: PS-b-P4VP(AzoCN)<PS-b-P4VP(AzoCH3)<PS-b-P4VP(AzoH). This result indicates that the electron donor group (CH3) and the electron acceptor group (CN) can lower the ablation threshold of PS-b-P4VP(AzoR).