Robust Metal-Decorated Polymer/Single-Walled Carbon Nanotube Composites for Gas Sensing

Presenter: 

Bora Yoon

Authors: 

Bora Yoon, Sophie F. Liu, Timothy M. Swager

Author Affiliation: 

Department of Chemistry, Massachusetts Institute of Technology

Abstract: 

A novel platform for electronic gas detectors was developed from poly(4-vinylpyridine) (P4VP) immobilized onto a glass substrate. To fabricate these devices, the glass substrate was decorated with gold electrodes and then subjected to organosilanization with 3-bromopropyltrichlorosilane. The resulting pendant alkyl bromide groups on the glass surface are then available to undergo quaternization chemistry with the pyridyl groups in a composite of P4VP and single-walled carbon nanotubes (SWCNTs), thereby covalently bonding the polymer to the substrate. Residual pyridyl groups in the P4VP that are not consumed in the quaternization can subsequently be used to coordinate metal nanoparticles or ions chosen to confer further selectivity or sensitivity to the device. After optimization of this platformÕs physical parameters using P4VP coordinated with Ag nanoparticles to detect ammonia gas, we use the modularity of the P4VP platform to demonstrate that incorporation of soft Lewis acidic Pd(II) cations from PdCl2 yields a selective and highly sensitive device that changes resistance upon exposure to vapors of thioethers, which have relevance in applications such as odorized fuel leak detection, produce detection and assessment, and breath diagnostics.