TY - JOUR

T1 - A study of smart hydrogels as sensing elements in gaseous environment for VOC detection

AU - Wang, Sitao

AU - Gerlach, Gerald

AU - Körner, Julia

N1 - Funding Information: This work was supported by the Research Training Group “Hydrogel-based microsystems” ( GRK 1865 ), funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) . Furthermore, the authors would like to thank Alice Mieting and Stefan Schreiber for results discussion and Daniela Franke for theoretical guidance. Schematic figures are created by Figdraw ( www.figdraw.com ).

PY - 2023/6/13

Y1 - 2023/6/13

N2 - Early-stage disease detection by volatile organic compounds (VOCs) monitoring in breath is a rapidly emerging field of research. Development of corresponding sensors requires highly sensitive and selective sensing elements that can ideally be adjusted for specific target VOCs or biomarker footprints. Smart hydrogels are very interesting candidates for sensing elements, specifically in the biomedical context, as they exhibit a reversible swelling change in response to external stimuli. Moreover, they can easily be tailored for biocompatibility, selectivity and specificity to target analytes. Hence, they could be very promising for VOC detection. However, their applications are so far limited to liquid environments as the swelling response is based on the uptake and release of liquid. The performance in gaseous environments has not been investigated in depth so far. Here, we therefore present a first study of different synthetic acrylamide-based smart hydrogels for use in ambient air with varying relative humidity and investigate their potential for VOC detection with the test analytes acetone and isopropanol. We find that the studied hydrogels (i) maintain their swelling response even in low humidity and present a measurable weight change, (ii) exhibit a distinct response for acetone and isopropanol, and that (iii) PNIPAAm-based hydrogels show the largest response for both analytes and allow a discrimination between them. Conclusively, we demonstrate the feasibility of smart hydrogels as sensing elements for VOCs detection in gaseous environments.

AB - Early-stage disease detection by volatile organic compounds (VOCs) monitoring in breath is a rapidly emerging field of research. Development of corresponding sensors requires highly sensitive and selective sensing elements that can ideally be adjusted for specific target VOCs or biomarker footprints. Smart hydrogels are very interesting candidates for sensing elements, specifically in the biomedical context, as they exhibit a reversible swelling change in response to external stimuli. Moreover, they can easily be tailored for biocompatibility, selectivity and specificity to target analytes. Hence, they could be very promising for VOC detection. However, their applications are so far limited to liquid environments as the swelling response is based on the uptake and release of liquid. The performance in gaseous environments has not been investigated in depth so far. Here, we therefore present a first study of different synthetic acrylamide-based smart hydrogels for use in ambient air with varying relative humidity and investigate their potential for VOC detection with the test analytes acetone and isopropanol. We find that the studied hydrogels (i) maintain their swelling response even in low humidity and present a measurable weight change, (ii) exhibit a distinct response for acetone and isopropanol, and that (iii) PNIPAAm-based hydrogels show the largest response for both analytes and allow a discrimination between them. Conclusively, we demonstrate the feasibility of smart hydrogels as sensing elements for VOCs detection in gaseous environments.

KW - Acetone

KW - Gas sensor

KW - Gaseous environment

KW - Isopropanol

KW - Relative humidity

KW - Sensing element

KW - Smart hydrogel

KW - Volatile organic compounds

UR - http://www.scopus.com/inward/record.url?scp=85158901036&partnerID=8YFLogxK

U2 - 10.1016/j.polymer.2023.126009

DO - 10.1016/j.polymer.2023.126009

M3 - Article

AN - SCOPUS:85158901036

VL - 278

JO - POLYMER

JF - POLYMER

SN - 0032-3861

M1 - 126009

ER -