Synthesis and characterisation of spiropyran-polymer brushes in micro-capillaries: Towards an integrated optical sensor for continuous flow analysis

Fused silica-capillaries were successfully functionalised with spiropyran-polymer brushes using spiropyran functionalised norbornyl derivative as monomer. The polymerisation was achieved by surface-initiated ring-opening metathesis polymerisation. A three-dimensional arrangement, covalently attached to the inner wall of the fused-silica capillary, was obtained. The spiropyran moiety has the freedom to open and close in response to light (ultraviolet, white light) within the polymer brushes. The coating was fully characterised by scanning electron microscopy, absorbance measurements and kinetic studies. The photo-response of the coatings showed very good reproducibility comparable with spiropyran monomers in solution demonstrating that this platform can be used for the development of capillary integrated sensors based on the inherited sensing proprieties of spiropyran moieties.