title: Sorption and Diffusion of Water Vapor and Carbon Dioxide in Sulfonated Polyaniline as Chemical Sensing Materials.
abstract: A hybrid quantum mechanics (QM)/molecular dynamics (MD) simulation is performed to investigate the effect of an ionizable group (-SO₃(-)Na⁺) on polyaniline as gas sensing materials. Polymers considered for this work include emeraldine base of polyaniline (EB-PANI) and its derivatives (Na-SPANI (I), (II) and (III)) whose rings are partly monosubstituted by -SO₃(-)Na⁺. The hybrid simulation results show that the adsorption energy, Mulliken charge and band gap of analytes (CO₂ and H₂O) in polyaniline are relatively sensitive to the position and the amounts of -SO₃(-)Na⁺, and these parameters would affect the sensitivity of Na-SPANI/EB-PANI towards CO₂. The sensitivity of Na-SPANI (III)/EB-PANI towards CO₂ can be greatly improved by two orders of magnitude, which is in agreement with the experimental study. In addition, we also demonstrate that introducing -SO₃(-)Na⁺ groups at the rings can notably affect the gas transport properties of polyaniline. Comparative studies indicate that the effect of ionizable group on polyaniline as gas sensing materials for the polar gas molecule (H₂O) is more significant than that for the nonpolar gas molecule (CO₂). These findings contribute in the functionalization-induced variations of the material properties of polyaniline for CO₂ sensing and the design of new polyaniline with desired sensing properties.
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. lqh91@outlook.com.
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Liang
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. jiangjunke92@outlook.com.
authors.forename: Junke
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Optoelectronic Technology & Systems, Education Ministry of China, Chongqing University and College of Opto-electronic Engineering, Chongqing University, Chongqing 400044, China. huaiyuye@163.com.
authors.forename: Huaiyu
authors.initials: H
authors.lastname: Ye
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. joeyoung0014@163.com.
authors.forename: Ning
authors.initials: N
authors.lastname: Yang
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. caimiao105@163.com.
authors.forename: Miao
authors.initials: M
authors.lastname: Cai
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. xiaojing@guet.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Faculty of Electromechanical Engineering, Guilin University of Electronic Technology, Guilin 541004, China. xianpingchen1979@126.com.|Key Laboratory of Optoelectronic Technology & Systems, Education Ministry of China, Chongqing University and College of Opto-electronic Engineering, Chongqing University, Chongqing 400044, China. xianpingchen1979@126.com.
authors.forename: Xianping
authors.initials: X
authors.lastname: Chen
keywords: adsorption; diffusion; gas sensors; polyaniline; sensitivity