Manipulating polymer composition to create low-cost, high-fidelity sensors for indoor CO2 monitoring

Zachary A Siefker; John N Hodul; Xikang Zhao; Nikhil Bajaj; Kelly M Brayton; Carsten Flores-Hansen; Wenchao Zhao; George T-C Chiu; James E Braun; Jeffrey F Rhoads; Bryan W Boudouris

doi:10.1038/s41598-021-92181-4

Manipulating polymer composition to create low-cost, high-fidelity sensors for indoor CO₂ monitoring

Sci Rep. 2021 Jun 24;11(1):13237. doi: 10.1038/s41598-021-92181-4.

Authors

Zachary A Siefker^{1

2}, John N Hodul³, Xikang Zhao⁴, Nikhil Bajaj^{1

2

5}, Kelly M Brayton⁴, Carsten Flores-Hansen³, Wenchao Zhao⁴, George T-C Chiu^{1

2

5}, James E Braun^{1

2}, Jeffrey F Rhoads^{6

7

8}, Bryan W Boudouris^{9

10}

Affiliations

¹ School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
² Ray W. Herrick Laboratories, Purdue University, West Lafayette, IN, 47907, USA.
³ Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
⁴ Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
⁵ Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA.
⁶ School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA. jfrhoads@purdue.edu.
⁷ Ray W. Herrick Laboratories, Purdue University, West Lafayette, IN, 47907, USA. jfrhoads@purdue.edu.
⁸ Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA. jfrhoads@purdue.edu.
⁹ Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA. boudouris@purdue.edu.
¹⁰ Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, 47907, USA. boudouris@purdue.edu.

Abstract

Carbon dioxide (CO₂) has been linked to many deleterious health effects, and it has also been used as a proxy for building occupancy measurements. These applications have created a need for low-cost and low-power CO₂ sensors that can be seamlessly incorporated into existing buildings. We report a resonant mass sensor coated with a solution-processable polymer blend of poly(ethylene oxide) (PEO) and poly(ethyleneimine) (PEI) for the detection of CO₂ across multiple use conditions. Controlling the polymer blend composition and nanostructure enabled better transport of the analyte gas into the sensing layer, which allowed for significantly enhanced CO₂ sensing relative to the state of the art. Moreover, the hydrophilic nature of PEO resulted in water uptake, which provided for higher sensing sensitivity at elevated humidity conditions. Therefore, this key integration of materials and resonant sensor platform could be a potential solution in the future for CO₂ monitoring in smart infrastructure.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.