1 research outputs found
Photoswitchable Layer-by-Layer Coatings Based on Photochromic Polynorbornenes Bearing Spiropyran Side Groups
Herein, we present
the synthesis of linear photochromic norbornene
polymers bearing spiropyran side groups (poly(SP-R)) and their assembly
into layer-by-layer (LbL) films on glass substrates when converted
to poly(MC-R) under UV irradiation. The LbL films were composed of
bilayers of poly(allylamine hydrochloride) (PAH) and poly(MC-R), forming
(PAH/poly(MC-R))<sub><i>n</i></sub> coatings. The merocyanine
(MC) form presents a significant absorption band in the visible spectral
region, which allowed tracking of the LbL deposition process by UV–vis
spectroscopy, which showed a linear increase of the characteristic
MC absorbance band with increasing number of bilayers. The thickness
and morphology of the (PAH/poly(MC-R))<sub><i>n</i></sub> films were characterized by ellipsometry and scanning electron microscopy,
respectively, with a height of ∼27.5 nm for the first bilayer
and an overall height of ∼165 nm for the (PAH/poly(MC-R))<sub>5</sub> multilayer film. Prolonged white light irradiation (22 h)
resulted in a gradual decrease of the MC band by 90.4 ± 2.9%
relative to the baseline, indicating the potential application of
these films as coatings for photocontrolled delivery systems