Modeling the resistive viscoelasticity of conductive polymer composites for sensor usage

Mu, Quanyi; Wang, Jikun; Xiao, Kun

doi:10.1039/d2sm01463g

Cited by 6 publications

(5 citation statements)

References 48 publications

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“…Also not discussed previously is the similarity of the resistance–strain relationship of these materials to the stress–strain relationship of viscoelastic materials. Other authors have noticed this similarity and introduced phenomenological models of the “viscoelastic resistivity” of such materials that are capable of fitting the resistivity‐strain data, while acknowledging the complex array of factors that could be affecting the conductivity of these materials under strain, including transversal contraction, as well as filler rearrangement and reorientation 77–79 …”

Section: Resultsmentioning

confidence: 99%

“…Other authors have noticed this similarity and introduced phenomenological models of the "viscoelastic resistivity" of such materials that are capable of fitting the resistivitystrain data, while acknowledging the complex array of factors that could be affecting the conductivity of these materials under strain, including transversal contraction, as well as filler rearrangement and reorientation. [77][78][79] It seems likely that, in general, changes to the particle network structure are a more significant cause of piezoresistivity than volumetric change. The work presented here lays the ground for an improved understanding of the complex relationship between deformation and network structure.…”

Section: Other Considerationsmentioning

confidence: 99%

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The incompressibility assumption and piezoresistivity in stretchable conductive composites

Ritchie,

Pahl,

Anderson

2024

J of Applied Polymer Sci

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Stretchable electronic conductors are vital components in soft robotics and flexible electronics. One method for producing these is combining conductive filler with a nonconductive elastomer. These composites commonly exhibit significant piezoresistivity. This work examines various mechanisms that may underlie this effect. These composites are generally analyzed through percolation theory, which describes the nonlinear relationship between filler volume fraction and conductivity. However, it is unclear whether percolation theory can explain their piezoresistivity or whether mechanisms such as rearrangement of the conductive network under deformation must be considered. This work compares volumetric change in the context of percolation theory against network rearrangement to examine the relative significance of these factors in determining piezoresistivity. Digital image correlation is utilized to investigate volumetric changes in carbon‐black silicone composites and finds that the typical assumption of incompressibility is reasonable, suggesting that volumetric changes alone cannot account for the behavior. A computational model is also developed, which implies that network rearrangement is likely a more significant factor and that interparticle interactions are crucial in understanding this effect. It was found that the most realistic modeling results were achieved only when both rigid and attractive interparticle interactions were accounted for in the model.

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Section: Resultsmentioning

confidence: 99%

Section: Other Considerationsmentioning

confidence: 99%

The incompressibility assumption and piezoresistivity in stretchable conductive composites

Ritchie,

Pahl,

Anderson

2024

J of Applied Polymer Sci

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“…Despite the widespread awareness and utilization of this effect, a consensus as to the mechanisms underlying it has yet to emerge, with various works attributing it to volumetric change [15,17], particle reorientation [18][19][20], and network rearrangement and nanocavitation [21,22]. Phenomenological viscoelastic models have been successful in modelling the time dependent behaviour of the resistance [14,23], but a clear link between the viscoelasticity of the polymer and the time dependent piezoresistivity has not yet been established. This work presents the results of a structured characterization scheme investigating the factors affecting the piezoresistivity of carbon-elastomer composites, focusing on two widely available and commonly used PDMS (silicone) elastomers.…”

Section: Introductionmentioning

confidence: 99%

Electromechanical characterization of piezoresistive carbon-elastomer composites

Ritchie,

Henke,

Pahl

et al. 2024

Electroactive Polymer Actuators and Devices (EAPAD) XXVI

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Stretchable electronic conductors are an important class of material enabling electroactive polymer (EAP) research. One of the most common approaches to creating a stretchable conductor is to embed conductive particles within a nonconductive matrix material to create a composite with favourable electromechanical properties. Whether an EAP device employs these composites for specific functions like strain sensing or simply as deformable electronic interconnects, the interplay between mechanical deformation and electronic conductivity frequently emerges as a central concern. While these materials are simple to produce, the relationship between mechanical strain and changes in electrical resistivity (piezoresistivity) can be complex and difficult to predict, and the factors that influence this behaviour are not well understood. This study focused on the comprehensive electromechanical characterization of various samples of piezoresistive elastomer composites. The work examined how a range of factors such as filler loading, matrix material, strain properties, additives, and production methodologies affected the piezoresistive properties of these composites. This work identifies key factors that can affect the magnitude, time dependence, and even direction of piezoresistivity. By identifying important influencing factors, the results of this work are intended to assist researchers in designing materials that are best suited for their specific use case.

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“…In CPCs-based strain sensors, the insulating polymer matrix provides flexibility and stretchability, while the conductive materials construct the conductive sensor network. Due to the viscoelastic nature of the polymer matrix, the CPCs-based strain sensors exhibit resistive viscoelasticity properties [ 7 , 8 , 9 ], such as rate dependence [ 10 , 11 ], relaxation [ 12 , 13 ], hysteresis [ 14 , 15 ], and dynamic resistance response [ 16 ]. Resistive viscoelasticity affects performance parameters such as linearity, sensitivity, repeatability, cycle stability, etc., which are critical for evaluating strain sensor materials [ 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, a micromechanical piezoresistive model study showed that the time-dependent transverse deformation leads to network compaction and is the mechanism behind resistance relaxation and hysteresis [ 21 ]. Combing the tunneling theory, a multi-branch model was developed, which used only a single set of parameters to predict the resistance relaxation behaviors of CPCs under different strains and different loading rates [ 11 ]. Zhang et al found that resistance drift/decay for most CPCs under quasi-static and dynamic loadings is a consequence of the relaxation of both the polymer chains and the conductive network [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

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

Tian

et al. 2023

Polymers

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Soft strain sensors based on conductive polymer composites (CPCs) provide a simple and feasible detection tool in wearable electronics, soft machines, electronic skin, etc. However, the CPCs-based soft strain sensors exhibit resistive viscoelasticity (or time-dependent properties) that hinder the intuitive reflection of the accurate strain and a simple calibration process. In this paper, CPCs with different carbon nanotubes (CNTs) and carbon black (CB) contents were prepared, and electro-mechanical experiments were conducted to study the effect of filler dimensionality and content on the resistive viscoelasticity of CPCs, aimed at guiding the fabrication of CPCs with low resistive viscoelasticity. Furthermore, resistive viscoelasticity and mechanical viscoelasticity were compared to study the origin of the resistive viscoelasticity of CPCs. We found that, at the vicinity of their percolation threshold, the CPCs exhibit high resistive viscoelasticity despite their high sensitivity. In addition, the secondary peaks for CB/SR composite were negligible when the CB concentration was low. Generally, compared with one-dimensional CNT-filled CPCs, the zero-dimensional CB-filled CPCs show higher sensitivity, lower resistive hysteresis, lower resistance relaxation ratio, and better cyclic performance, so they are more suitable for sensor usage. By comparing the resistive viscoelasticity and mechanical viscoelasticity of CPCs, it is indicated that, when the concentration of nanoparticles (NPs) approaches the percolation thresholds, the resistive viscoelasticity is mainly derived from the change of conductive network, while when the concentration of NPs is higher, it is primarily due to the unrecoverable deformations inside the material.

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Modeling the resistive viscoelasticity of conductive polymer composites for sensor usage

Abstract: With the development of fully printed electronics, soft sensors are in demand in various fields, such as wearable electronics, soft machines, etc. Most soft resistive sensors are made of conductive...

Cited by 6 publications

References 48 publications

The incompressibility assumption and piezoresistivity in stretchable conductive composites

The incompressibility assumption and piezoresistivity in stretchable conductive composites

Electromechanical characterization of piezoresistive carbon-elastomer composites

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

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