Novel pH-sensitive photopolymer hydrogel and its holographic sensing response for solution characterization. (May 2018)

• Record Type: Journal Article
• Authors: Liu, Hongpeng; Yu, Dan; Zhou, Ke; Wang, Shichan; Luo, Suhua; Li, Li; Wang, Weibo; Song, Qinggong
• Is Part Of: Optics & laser technology. Volume 101(2018)
• Page Start: 257
• Page End: 267
• Publication Date: 2018-05
• Subjects: Holographic sensor -- Polymer hydrogel -- Holographic volume grating -- Photopolymer -- Diffraction spectrum; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2017.11.025
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Novel photosensitive polymer hydrogel is developed for constructing holographic sensor. Sensing response of photosensitive polymer hydrogel is characterized to evaluate pH sensitivity of buffer. Theoretical model is deduced to describe the dynamic grating formation and sensing process. Abstract: Optical sensor based on pH-sensitive hydrogel has important practical applications in medical diagnosis and bio-sensor areas. This report details the experimental and theoretical results from a novel photosensitive polymer hydrogel holographic sensor, which formed by thermal polymerization of 2-hydroxyethyl methacrylate, for the detection of pH in buffer. Volume grating recorded in the polymer hydrogel was employed in response to the performance of solution. Methacrylic acid with carboxyl groups was selected as the primary co-monomer to functionalize the matrix. Peak diffraction spectrum of holographic grating determined as a primary sensing parameter was characterized to reflect the change in pH. The extracted linear relation between peak wavelength and pH value provided a probability for the practical application of holographic sensor. To explore the sensing mechanism deeply, a theoretical model was used to describe the relevant holographic processes, including grating formation, dark diffusional enhancement, and final fringe swelling. Numerical result further showed all of the dynamic processes and internal sensing physical mechanism. These experimental and numerical results provided a significant foundation for the development of novel holographic sensor based on polymer hydrogel and improvement of its practical applicability.