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Poly(vinyl alcohol) Rehydratable Photonic Crystal Sensor Materials
Author(s) -
Muscatello Michelle M. Ward,
Asher Sanford A.
Publication year - 2008
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200701210
Subject(s) - vinyl alcohol , materials science , photonic crystal , diffraction , swelling , polymer , chemical engineering , ion , colloidal crystal , self healing hydrogels , colloid , crystal (programming language) , nanoparticle , nanotechnology , polymer chemistry , optoelectronics , composite material , optics , organic chemistry , chemistry , physics , computer science , programming language , engineering
We developed a new photonic crystal hydrogel material based on the biocompatible polymer poly (vinyl alcohol) (PVA), which can be reversibly dehydrated and rehydrated, without the use of additional fillers, while retaining the diffraction and swelling properties of polymerized crystalline colloidal arrays (PCCA). This chemically modified PVA hydrogel photonic crystal efficiently diffracts light from the embedded crystalline colloidal array. This diffraction optically reports on volume changes occurring in the hydrogel by shifts in the wavelength of the diffracted light. We fabricated a pH sensor, which demonstrates a 350 nm wavelength shift between pH values of 3.3 and 8.5. We have also fabricated a Pb +2 sensor, in which pendant crown ether groups bind lead ions. Immobilization of the ions within the hydrogel increases the osmotic pressure due to the formation of a Donnan potential, swelling the hydrogel and shifting the observed diffraction in proportion to the concentration of bound ions. The sensing responses of rehydrated PVA pH and Pb +2 sensors were similar to that before drying. This reversibility of rehydration enables storage of these hydrogel photonic crystal sensors in the dry state, which makes them much more useful for commercial applications.