Two-dimensional inverse opal hydrogel for pH sensing

Abstract

A novel hydrogel film with a highly ordered macropore monolayer on its surface was prepared by templated photo-polymerization of hydrogel monomers on a two-dimensional (2D) polystyrene colloidal array. The 2D inverse opal hydrogel has prominent advantages over traditional three-dimensional (3D) inverse opal hydrogels. First, the formation of the 2D array template through a self-assembly method is considerably faster and simpler. Second, the stable ordering structure of the 2D array template makes it easier to introduce the polymerization solution into the template. Third, a simple measurement, a Debye diffraction ring, is utilized to characterize the neighboring pore spacing of the 2D inverse opal hydrogel. Acrylic acid was copolymerized into the hydrogel; thus, the hydrogel responded to pH through volume change, which resulted from the formation of the Donnan potential. The 2D inverse opal hydrogel showed that the neighboring pore spacing increased by about 150 nm and diffracted color red-shifted from blue to red as the pH increased from pH 2 to 7. In addition, the pH response kinetics and ionic strength effect of this 2D mesoporous polymer film were also investigated.

Photonic Crystal Stimuli-Responsive Chromatic Sensors: A Short Review

“…Applying the Debye ring approach, several types of sensors were developed, such as the pH-sensitive system demonstrated by Xue et al [40], that presents a large dynamic range, from 620 to 668 nm, in a pH interval between 3.22 and 7.91. Another hydrogel pH sensor was implemented by Cai et al [39] by crosslinking chitosan with glutaraldehyde; the diffraction maximum shifted from 535 nm at pH 7 to 645 nm at pH 5.…”

Clinical Evaluation of a Photonic Crystal Sensor for Glucose Monitoring in Urine

“…Photonic crystal (PhC) sensors have been increasingly considered as POCT devices for chemical and biological analysise, for instance the fast and low‐cost detection of pH, proteins, organophosphates, and glucose . PhC sensors combine the recognition functional group with the signal conversion group of CCA, all embedded in hydrogel to get PCCA.…”

Binary phase solid‐state photopolymerization behavior of acrylate cryogels under different light sources

“…Chemical crosslinking using monomers is the only well‐recognized method of synthesizing these polymer gels, and one of the conventional but critical crosslinking techniques is photopolymerization . This solid‐state photopolymerization can be used for the synthesis of crosslinked polymer gels using monomers via photoinitiators in the presence of ultraviolet (UV) light …”

“…A high‐pressure Hg arc lamp has primarily been reported to be employed in the photopolymerization of cryogels . However, owing to the prolonged rate of reaction, the polymerization reaction often does not complete, leaving behind a significantly large number of unreacted double bonds in the polymer matrix . Such unreacted matter may result in allergic, cytotoxic, and genotoxic effects.…”