Sensitive Organic Vapor Sensors Based on Flexible Porous Conductive Composites with Multilevel Pores and Thin, Rough, Hollow-Wall Structure

Abstract

Advanced organic vapor sensors that simultaneously have high sensitivity, fast response, and good reproducibility are required. Herein, flexible, robust, and conductive vapor-grown carbon fibers (VGCFs)-filled polydimethylsiloxane (PDMS) porous composites (VGCFs/PDMS sponge (CPS)) with multilevel pores and thin, rough, and hollows wall were prepared based on the sacrificial template method and a simple dip-spin-coating process. The optimized material showed outstanding mechanical elasticity and durability, good electrical conductivity and hydrophobicity, as well as excellent acid and alkali tolerance. Additionally, CPS exhibited good reproducible sensing behavior, with a high sensitivity of ~1.5 × 105 s−1 for both static and flowing organic vapor, which was not affected in cases such as 20% squeezing deformation or environment humidity distraction (20~60% RH). Interestingly, both the reproducibility and sensitivity of CPS were better than those of film-shaped VGCFs/PDMS (CP), which has a thickness of two hundred microns. Therefore, the contradiction between the reproducibility and high sensitivity was well-solved here. The above excellent performance could be ascribed to the unique porous structures and the rough, thin, hollow wall of CPS, providing various gas channels and large contact areas for organic vapor penetration and diffusion. This work paves a new way for developing advanced vapor sensors by optimizing and tailoring the pore structure.

The Effect of Filler Dimensionality and Content on Resistive Viscoelasticity of Conductive Polymer Composites for Soft Strain Sensors

“…In addition, the modulus of CB/SR composite is smaller than that of the CNT/SR composite with the same filler content, making it more suitable for soft sensors. It should be noted that, in addition to electrical and mechanical properties, environmental factors such as humidity should also be characterized to ensure that the CPCs have good environmental stability [ 40 ].…”

Porous Structural Microfluidic Device for Biomedical Diagnosis: A Review

“…Due to the simplicity, safety and low cost of preparation, the sacrificial template method is commonly used to obtain porous PDMS sponges [ 36 , 77 ]. The successful fabrication of porous PDMS using sugar as a template and water as a solvent was first reported by Choi et al [ 35 ].…”

Progress in Microtopography Optimization of Polymers-Based Pressure/Strain Sensors

“…Among them, PDMS is the most widely used material because of its excellent comprehensive performance, not only as a flexible substrate, but also as a pressure-sensing layer. So far, PDMS-based composite pressure/strain sensors have been manufactured by combining various elements, such as metal nanomaterials (e.g., metal particles [ 31 ] and metal nanowires/networks [ 32 , 33 , 34 , 35 ]), carbon materials (e.g., carbon nanotubes (CNT), graphene/graphene oxide (GO), and carbon black (CB)), and other hybrid micro/nano-composites [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ].…”

“…Another method used to characterize response time is to count the frequency response, and the frequency signal can be easily converted into a pulse signal with any desired amplitude through data processing or additional circuits (such as an edge detector) [ 100 ]. High time resolution means faster and more accurate dynamic detection [ 37 , 43 ].…”