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Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors

Swellable polymer microspheres that respond to pH were prepared by free radical dispersion polymerization using N-isopropylacrylamide (NIPA), N,N(′)-methylenebisacrylamide (MBA), 2,2-dimethoxy-2-phenylacetylphenone, N-tert-butylacrylamide (NTBA), and a pH-sensitive functional comonomer (acrylic acid...

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Autores principales: Lavine, Barry K., Kaval, Necati, Oxenford, Leah, Kim, Mariya, Dahal, Kaushalya Sharma, Perera, Nuwan, Seitz, Rudolf, Moulton, James T., Bunce, Richard A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8512897/
https://www.ncbi.nlm.nih.gov/pubmed/34640813
http://dx.doi.org/10.3390/s21196493
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author Lavine, Barry K.
Kaval, Necati
Oxenford, Leah
Kim, Mariya
Dahal, Kaushalya Sharma
Perera, Nuwan
Seitz, Rudolf
Moulton, James T.
Bunce, Richard A.
author_facet Lavine, Barry K.
Kaval, Necati
Oxenford, Leah
Kim, Mariya
Dahal, Kaushalya Sharma
Perera, Nuwan
Seitz, Rudolf
Moulton, James T.
Bunce, Richard A.
author_sort Lavine, Barry K.
collection PubMed
description Swellable polymer microspheres that respond to pH were prepared by free radical dispersion polymerization using N-isopropylacrylamide (NIPA), N,N(′)-methylenebisacrylamide (MBA), 2,2-dimethoxy-2-phenylacetylphenone, N-tert-butylacrylamide (NTBA), and a pH-sensitive functional comonomer (acrylic acid, methacrylic acid, ethacrylic acid, or propacrylic acid). The diameter of the microspheres was between 0.5 and 1.0 μm. These microspheres were cast into hydrogel membranes prepared by mixing the pH-sensitive swellable polymer particles with aqueous polyvinyl alcohol (PVA) solutions followed by crosslinking with glutaric dialdehyde for use as pH sensors. Large changes in the turbidity of the PVA membrane were observed as the pH of the buffer solution in contact with the membrane was varied. These changes were monitored by UV–visible absorbance spectroscopy. Polymer swelling of many NIPA copolymers was reversible and independent of the ionic strength of the buffer solution in contact with the membrane. Both the degree of swelling and the apparent pK(a) of the polymer microspheres increased with temperature. Furthermore, the apparent pK(a) of the polymer particles could be tuned to respond sharply to pH in a broad range (pH 4.0–7.0) by varying the amount of crosslinker (MBA) and transition temperature modifier (NTBA), and the amount, pK(a), and hydrophobicity of the pH-sensitive functional comonomer (alkyl acrylic acid) used in the formulation. Potential applications of these polymer particles include fiber optic pH sensing where the pH-sensitive material can be immobilized on the distol end of an optical fiber.
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spelling pubmed-85128972021-10-14 Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors Lavine, Barry K. Kaval, Necati Oxenford, Leah Kim, Mariya Dahal, Kaushalya Sharma Perera, Nuwan Seitz, Rudolf Moulton, James T. Bunce, Richard A. Sensors (Basel) Article Swellable polymer microspheres that respond to pH were prepared by free radical dispersion polymerization using N-isopropylacrylamide (NIPA), N,N(′)-methylenebisacrylamide (MBA), 2,2-dimethoxy-2-phenylacetylphenone, N-tert-butylacrylamide (NTBA), and a pH-sensitive functional comonomer (acrylic acid, methacrylic acid, ethacrylic acid, or propacrylic acid). The diameter of the microspheres was between 0.5 and 1.0 μm. These microspheres were cast into hydrogel membranes prepared by mixing the pH-sensitive swellable polymer particles with aqueous polyvinyl alcohol (PVA) solutions followed by crosslinking with glutaric dialdehyde for use as pH sensors. Large changes in the turbidity of the PVA membrane were observed as the pH of the buffer solution in contact with the membrane was varied. These changes were monitored by UV–visible absorbance spectroscopy. Polymer swelling of many NIPA copolymers was reversible and independent of the ionic strength of the buffer solution in contact with the membrane. Both the degree of swelling and the apparent pK(a) of the polymer microspheres increased with temperature. Furthermore, the apparent pK(a) of the polymer particles could be tuned to respond sharply to pH in a broad range (pH 4.0–7.0) by varying the amount of crosslinker (MBA) and transition temperature modifier (NTBA), and the amount, pK(a), and hydrophobicity of the pH-sensitive functional comonomer (alkyl acrylic acid) used in the formulation. Potential applications of these polymer particles include fiber optic pH sensing where the pH-sensitive material can be immobilized on the distol end of an optical fiber. MDPI 2021-09-29 /pmc/articles/PMC8512897/ /pubmed/34640813 http://dx.doi.org/10.3390/s21196493 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Lavine, Barry K.
Kaval, Necati
Oxenford, Leah
Kim, Mariya
Dahal, Kaushalya Sharma
Perera, Nuwan
Seitz, Rudolf
Moulton, James T.
Bunce, Richard A.
Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title_full Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title_fullStr Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title_full_unstemmed Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title_short Synthesis and Characterization of N-Isopropylacrylamide Microspheres as pH Sensors
title_sort synthesis and characterization of n-isopropylacrylamide microspheres as ph sensors
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8512897/
https://www.ncbi.nlm.nih.gov/pubmed/34640813
http://dx.doi.org/10.3390/s21196493
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