Polydimethylsiloxane Composites Research Articles

Liquid Metal-Based Elastomer Composite with Selective Switchable Adhesion to Solids.

Selective switchable adhesion has recently attracted much attention due to its wide applications in transfer printing, information transfer, and flexible electronics. However, selective adhesive materials often have a complex adhesion or preparation process, which limits their use. To overcome this problem, this study prepares a composite of liquid metal foam and polydimethylsiloxane (PDMS) with selective photocontrolled adhesion, which can directly adhere to solids at room temperature. Utilizing the photoinduced phase transition of liquid metals, solid adhesion can be regulated by changing the backing layer modulus of the adhesive layer. Since the phase transition process is gradually completed by heat transfer from the illuminated side to the backlight side that adheres to the solid, the melting area on the backlight side can be regulated by controlling the light time, which determines the adhesion regulation area. Therefore, the accuracy of the adhesion regulation can reach less than 0.9 mm without relying on the accuracy of the infrared light. Moreover, based on the selective switchable adhesion, the selective transfer of solids with different scales can be achieved at room temperature. The findings of this study may provide strategies for the simple preparation of selective adhesive materials and the improvement of control accuracy.

Excellent Low-Frequency Microwave Absorption and High Thermal Conductivity in Polydimethylsiloxane Composites Endowed by Hydrangea-Like CoNi@BN Heterostructure Fillers.

The advancement of thin, lightweight, and high-power electronic devices has increasingly exacerbated issues related to electromagnetic interference and heat accumulation. To address these challenges, a spray-drying-sintering process is employed to assemble chain-like CoNi and flake boron nitride (BN) into hydrangea-like CoNi@BN heterostructure fillers. These fillers are then composited with polydimethylsiloxane (PDMS) to develop CoNi@BN/PDMS composites, which integrate low-frequency microwave absorption and thermal conductivity. When the volume fraction of CoNi@BN is 44 vol% and the mass ratio of CoNi to BN is 3:1, the CoNi@BN/PDMS composites exhibit optimal performance in both low-frequency microwave absorption and thermal conductivity. These composites achieve a minimum reflection loss of -49.9dB and a low-frequency effective absorption bandwidth of 2.40GHz (3.92-6.32GHz) at a thickness of 4.4mm, fully covering the n79 band (4.4-5.0GHz) for 5G communications. Meanwhile, the in-plane thermal conductivity (λ∥) of the CoNi@BN/PDMS composites is 7.31W m-1 K-1, which is ≈11.4 times of the λ∥ (0.64W m-1 K-1) for pure PDMS, and 32% higher than that of the (CoNi/BN)/PDMS composites (5.52W m-1 K-1) with the same volume fraction of CoNi and BN obtained through direct mixing.

Fraction-dependent filler network in silicone rubber: Unraveling abrupt enhancement in rheological properties via solvent extraction and DLS study

A pivotal nanofiller network will be constructed by the filler loading threshold inside the silicone rubber, leading to abrupt enhancement in the rheological properties of the composites. However, the contribution of the nanofiller network to the performance mutation is poorly understood due to lack of direct evidence to recognize the formation of filler networks. This work quantitatively investigated the filler aggregation network of solvent-extracted monodisperse silica-filled polydimethylsiloxane (PDMS) composites to interpret the rheological properties. The results indicated that, when filler loadings reach 60 phr, the size of the filler network reaches its maximum (1280.5 nm), significantly increasing the storage modulus (166 kPa) and Payne effect (163 kPa), due to the formation of a filler network confirmed by Dynamic Light Scattering (DLS) and scanning electron microscope (SEM) observation. The reduction in aggregate size observed with longer extraction times is because of the collapse of the nanofiller network, which occurs as the polymer chains are removed. The aggregates reappear in a monodisperse form as the extraction duration reaches 20 days. This confirms that filler aggregates of interconnected polymer chains can form a well-developed network structure that effectively supports and transfers stresses. This contributes to an in-depth understanding of the formation mechanism of nanofiller networks, aiding the advancement of high-performance polymer nanocomposites.

Triboelectric Nanogenerators Based on Transition Metal Carbo-Chalcogenide (Nb2S2C and Ta2S2C) for Energy Harvesting and Self-Powered Sensing.

With burgeoning considerations over energy issues and carbon emissions, energy harvesting devices such as triboelectric nanogenerators (TENGs) are developed to provide renewable and sustainable power. Enhancing electric output and other properties of TENGs during operation is the focus of research. Herein, two species (Nb2S2C and Ta2S2C) of a new family of 2D materials, Transition Metal Carbo-Chalcogenides (TMCCs), are first employed to develop TENGs with doping into Polydimethylsiloxane (PDMS). Compared with control samples, these two TMCC-based TENGs exhibit higher electric properties owing to the enhanced permittivity of PDMS composite, and the best performance is achieved at a concentration of 3wt. ‰ with open circuit voltage (Voc) of 112V, short circuit current (Isc) of 8.6µA and charge transfer (Qsc) of 175nC for Nb2S2C based TENG, and Voc of 127V, Isc of 9.6µA, and Qsc of 230nC for Ta2S2C based TENGs. These two TENGs show a maximum power density of 1360 and 911mWm-2 respectively. Moreover, the tribology performance is also evaluated with the same materials, revealing that the Ta2S2C/PDMS composite as the electronegative material presented a lower coefficient of friction (COF) than the Nb2S2C/PDMS composite. Their applications for energy harvesting and self-powered sensing are also demonstrated.

Development of a high-sensitivity and fast-response fiber temperature sensor utilizing Ti3C2TX MXene/PDMS composites and Vernier effect

Precisely measuring temperature holds great significance for human daily life and industrial production. A high-sensitivity and fast-response optical fiber temperature sensor based on the vernier effect is proposed. A Fabry-Perot interferometer (FPI) filled with Ti3C2TX MXene and polydimethylsiloxane (PDMS) composites is employed as a sensing probe for the first time, and a cascaded Mach-Zender interferometer (MZI) as a reference unit due to its insensitivity to temperature. The temperature sensitivity of the FPI filled with Ti3C2TX MXene/PDMS composites is 1.63 nm/°C owing to the excellent thermal expansion characteristics of PDMS, and the response time is shortened from 3.021 s to 719 ms compared to that of the FPI filled with pure PDMS attributed to the high thermal conductivity of MXene. The cascading of FPI and MZI with similar free spectral ranges generates the vernier effect. The sensitivity is magnified by 19.44 times, reaching up to 31.62 nm/°C in the range of 36.5 - 37.2 °C, and the response time is 721 ms. Furthermore, experimental results demonstrate the sensor’s good stability, implying its potential applications of the sensor in medical diagnosis, environmental monitoring and biosensing.

Flexible multifunctional polydimethylsiloxane composites with segregated structure fabricated by hydrophobic interaction for efficient electromagnetic interference shielding

Flexible multifunctional polydimethylsiloxane composites with segregated structure fabricated by hydrophobic interaction for efficient electromagnetic interference shielding

Development of Thyme-Infused Polydimethylsiloxane Composites for Enhanced Antibacterial Wound Dressings.

Polydimethylsiloxane (PDMS) is widely used in biomedical applications due to its biocompatibility and flexibility but faces challenges due to its hydrophobicity and limited mechanical strength. This study explores the incorporation of thyme (Thymus vulgaris L.) into PDMS to enhance its properties for wound dressing applications. PDMS composites containing 2.5 wt.% and 5 wt.% of thyme were prepared and evaluated for physical, chemical, mechanical, and biological properties. Scanning electron microscopy, contact angle measurements, absorption tests, Fourier-transform infrared spectroscopy, differential scanning calorimetry, hardness, tensile testing, antibacterial activity, and cell viability assays were conducted. Thyme integration improved mechanical properties with increased absorption and preserved hydrophobicity. FTIR and DSC analyses indicated minimally altered crystallinity and chemical interactions. Hardness decreased with higher thyme content due to terpene-induced polymerization inhibition. Tensile testing showed reduced stress at break but increased elongation, suitable for wound dressings. Enhanced antibacterial activity was observed, with composites meeting bacteriostatic standards. Cell viability exceeded 70%, with optimal results at 2.5 wt.% thyme, attributed to cytokine-inducing compounds. Thyme-incorporated PDMS composites exhibit improved antibacterial and mechanical properties, demonstrating the potential for advanced wound dressings.

Microwall array tactile sensor fabricated by transferring CNT/PDMS composite material into high aspect metal mold

This paper proposes a slip sensor that assists an industrial robot to grasp an object with the minimum force required. The sensor developed in this study can detect whether an object is being pressed or sliding inside the robot hand. The developed sensor was fabricated using a custom-made metal mold, which is a block of 20 mm square and 3 mm thick with lines and spaces of 0.4 mm pitch and 2 mm depth, forming a vertical wall array (50 in total) with finely high aspect ratio of 10, i.e., the height of each wall is 2 mm and the thickness is 0.2 mm. The flexible sensor body is obtained by pouring a composite of polydimethylsiloxane (PDMS) and carbon nanotubes (CNTs) into this mold, heating it to solidify it, and then releasing it from the mold. This sensor is intended to attach to the grasping surface of a robot hand. This sensor is a resistive one, i.e., changes in the sensor's internal circuitry when the robot hand grasps an object are expressed as changes in the sensor resistance. The sensor can both estimate the pressing force and detect the object slippage, since the resistance rapidly changes when a slippage occurs. This sensor allows the robot to detect the contact state with a handling object.

Molecular dynamics simulation of the thermal conductivity mechanism of polydimethylsiloxane composites filled by multilayer hexagonal boron nitride

To design polydimethylsiloxane (PDMS)-based nanocomposites with high thermal conductivity, multiscale simulations were adopted to study the effect of the modified hexagonal boron nitride (h-BN) and the layer number of h-BN on the interface improvement of nanocomposites. The results indicate that 6-aminocaproic acid (ACA) effectively improves the interfacial thermal conductivity of the composites. The interaction energy between h-BN modified by ACA (ACA@h-BN) and PDMS is enhanced compared to that of an unmodified h-BN/PDMS composite system. It's interesting that the change rate of thermal conductivity (δ) decreases first and then increases with the increase in the layer number of ACA@h-BN, and gradually increases to a value more equal to that of the single-layer system when the layer number of ACA@h-BN reaches 5. The interfacial thickness increases from 1.93 Å to 2.60 Å as the layer number of ACA@h-BN increases from 1 to 6, which is beneficial to improve the thermal conductivity. However, the matching coefficient (M) of the phonon vibration power spectrum between PDMS and ACA@h-BN decreases from 0.024 to 0.011 as the layer number of ACA@h-BN increases from 1 to 6, which impairs the thermal conductivity. The decrease in M dominates the δ in the composites filled by h-BN with 1–3 layers. The thermal conductivity is more affected by the specific gravity of ACA@h-BN than M in the composites filled by h-BN with 4–6 layers. It is proposed that the ideal single-layer ACA@h-BN can be replaced to some extent by the ACA@h-BN with 5 layers to improve the thermal properties of the composites. This work is expected to provide theoretical support for interface modification of nanocomposites, and preparation of high-thermal conductivity composites.

Fabrication of Synergistically Induced Carbon Fiber/Graphene Reinforced Polydimethylsiloxane Composites with High Thermal Conductivity

AbstractThis study compares thermal conductivity results of vertically orientated carbon fiber and graphene, polydimethylsiloxane (V‐CFG/PDMS) composites with randomly orientated R‐CFG/PDMS composites and pure PDMS to highlight the impact of aligned structure on thermal conductive properties. The results reveal that, at 25 wt.% filler loading R‐CFG/PDMS composites exhibit a thermal conductivity of 2.68 W m−1 K−1, while V‐CFG/PDMS achieves maximum thermal conductivity of 4.02 W m−1 K−1. This excellent performance of V‐CF/G PDMS can be attributed to the synergistic effects arising from the combination of carbon fiber and graphene.

Tailoring molecular structure and electromechanical properties of polydimethylsiloxane elastomer for enhanced energy conversion efficiency

AbstractThe molecular structure of dielectric elastomers dictates their mechanical, electrical, and properties to react under external stimuli, influencing their suitability for applications such as actuators, sensors, and energy harvesting devices. The molecular structure of polymers can be tailored by incorporating plasticizers and particulate fillers to achieve multifunctional properties. However, achieving a balance between flexibility and maintaining mechanical strength due to incorporation of fillers induced phase separation and compromised intermolecular interactions remains challenging. In the present work, polydimethylsiloxane (PDMS) composites are synthesized using plasticizer and particulate fillers, polyethylene glycol (H‐(OCH2CH2)nOH) and titanium diboride (TiB2) respectively in various concentrations using shear mixing and doctor blade casting technique. Molecular structure of synthesized PDMS composite is confirmed by observing peaks of Raman spectra sift, which exhibits robust CO bonds dominating for both fillers. Chain entanglement due to filler incorporation significantly affects the crosslink density of PDMS composite, it increases with the concentration of plasticizer and possesses inverse relation for particulate. Furthermore, interdependence of the filler types and concentration are found on the mechanical as well as electrical properties. The specific deformation energy exhibits a significant increase of 118.9% when comparing particulate to the plasticizer at concentration of 8 wt.%. Although plasticizer increases the actuation strain and energy conversion efficiency but decreases the electrical breakdown voltage in comparison to particulate. By systematically varying fillers concentration, subtle changes in multifunctional properties are achieved. Overall, this investigation provides a framework for tailoring dielectric elastomer composites with desired electromechanical characteristics through the amalgamation of filler types and crosslinking densities, all intricately tied to the molecular architecture for electromechanical sensors.Highlights Filler incorporation changes DE molecular structure and materials properties. Formation of additional bonds and micro‐capacitors in DE enhances capacitance. Actuation strain in DE depends on filler type and concentration. Energy conversion efficiency varies with the concentration of filler.

Fully 3D printed functional PDMS composites with designable structures and performances

Three-dimensional (3D) printing, as a layer-to-layer additive manufacturing technology, has received widespread attention for excellent designability. However, as for direct ink writing (DIW), current printing level is difficult to achieve high-precision printing of thermoset composites of different compositions. Therefore, fully 3D printing based on thermoset composites with high designability is proposed. The intralayer and interlayer of structure and materials prepared by this method are designable, and layer thicknesses as well as inter-layer patterns are adjustable. In this work, alumina (Al2O3) and short carbon fiber (SCF) are used as thermally conductive fillers, polydimethylsiloxane (PDMS) is conducted as thermoset matrix. Benefit from the high designability of our method, a series of Al2O3/SCF/Al2O3 (ASA) and SCF/Al2O3/SCF (SAS) composite samples with sandwich structures are fabricated and compared. The different materials and structural designs of these composite samples give them completely different properties in terms of thermal, electromagnetic shielding, and mechanical properties, making it possible to create customized designs for different scenarios. Taking thermal management materials (TMMs) as an example, we use this method to prepare ASA and SAS composites with sandwich structure, thermal conductivity of A40S30A40 and S30A40S30 reached 1.00 W/(m·K) and 1.55 W/(m·K) respectively. In all, customized and multifunctional applications make PDMS composites have a widespread prospect.

Consistent Thermal Conductivities of Spring-Like Structured Polydimethylsiloxane Composites under Large Deformation.

Flexible and highly thermally conductive materials with consistent thermal conductivity (λ) during large deformation are urgently required to address the heat accumulation in flexible electronics. In this study, spring-like thermal conduction pathways of silver nanowire (S-AgNW) fabricated by 3D printing are compounded with polydimethylsiloxane (PDMS) to prepare S-AgNW/PDMS composites with excellent and consistent λ during deformation. The S-AgNW/PDMS composites exhibit a λ of 7.63W m-1 K-1 at an AgNW amount of 20 vol%, which is ≈42 times that of PDMS (0.18W m-1 K-1) and higher than that of AgNW/PDMS composites with the same amount and random dispersion of AgNW (R-AgNW/PDMS) (5.37W m-1 K-1). Variations in the λ of 20 vol% S-AgNW/PDMS composites are less than 2% under a deformation of 200% elongation, 50% compression, or 180° bending, which benefits from the large deformation characteristics of S-AgNW. The heat-transfer coefficient (0.29W cm-2 K-1) of 20 vol% S-AgNW/PDMS composites is ≈1.3 times that of the 20 vol% R-AgNW/PDMS composites, which reduces the temperature of a full-stressed central processing unit by 6.8°C compared to that using the 20 vol% R-AgNW/PDMS composites as a thermally conductive material in the central processing unit.

Multifunctional Polymer Composites for Automatable Induction Heating with Subsequent Temperature Verification

Manipulating ferromagnetic particles using an alternating current (AC) magnetic field is a versatile method for quick, local, and on‐demand heat generation. These particles can be incorporated into various matrices as heating elements. Their heat release can be controlled by adjusting process or material parameters. Herein, a proof‐of‐concept for a flexible polymer composite with customizable magnetically triggered heat release due to prior object identification via fluorescence readout is presented. The maximum temperature resulting from this process can be determined through a second fluorescence readout ex post. This novel combination of functionalities results from the synergistic interaction of inductively heatable magnetic supraparticles (SPs) and luminescent communicating SPs in one polydimethylsiloxane composite. The surface of the composite can be heated to the maximum temperatures of choice in a range between 125 and 200 °C within 2 s. Heat release and temperature verification provide spatial resolution of millimeters. The identification signature and the working range of the temperature indication functionality of the composite are customizable by exploiting its modular material design. The temperature indication functionality of the composite offers spatial resolution and ex‐post readout at any point of interest, making it a versatile alternative to established optical thermometry methods.

Effect of reduced graphene oxide on vulcanization of polydimethylsiloxane composites

AbstractThis research aims to investigate the effect of reduced graphene oxide (rGO) on the kinetics of addition vulcanization in polydimethylsiloxane (PDMS) elastomers. For this purpose, the synthesis of graphene oxide (GO) and silane‐grafted GO followed by chemical reduction of particles was conducted to prepare rGOs with different surface chemistry. Particles were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction, scanning electron microscopy, and energy‐dispersive x‐ray analysis. Composites of PDMS containing these particles were prepared by solution mixing, and vulcanization of composites was investigated using differential scanning calorimetry. Results showed that the rate and degree of vulcanization reaction increase up to a critical concentration of particles and then decrease afterward. This behavior was attributed to the catalytic effect of chemical groups on the surface of rGOs, whereas the reverse behavior above the critical concentration was correlated to the immobilization of trapped rubber in the network of particles. Grafting graphene oxide by a long alkyl‐chain silane covered these chemical groups, suppressed the catalytic effect, improved the dispersion of particles, and shifted the critical concentration lower. The critical concentration was correlated to the electrical percolation threshold of particles and confirmed by the solvent swelling method. It was also shown that rGO can itself act as the catalyst for the vulcanization of PDMS with no need for platinum. As the dynamic‐mechanical‐thermal analysis showed, the PDMS composites containing 0.75 wt% of particles did not vulcanize properly. However, composites containing fewer particles were vulcanized.Highlights Reduced graphene oxide affects additional vulcanization of PDMS. Below a critical loading, rGO accelerates vulcanization by a catalytic effect. Above critical loading, rGO decelerates vulcanization by a networking effect. Surface groups of rGO control catalytic and networking mechanisms. Silane modification of rGO affects interfacial behavior, thus critical loading.

Water-Soluble, Self-Healing, and Debonding Primer for the Interface between Silicone Leather and Polydimethylsiloxane Composites.

The exceptional hydrophobicity and antifouling properties of polydimethylsiloxane (PDMS) composites have attracted extensive interest as a result of low surface energy. However, PDMS composites are hardly bound by common primers, greatly limiting their practical applications. To address this issue, an EPMS/VTMS (EV) primer synthesized by hydrolytic polycondensation of 3-[(2,3)-epoxypropoxypropyl]methyldiethoxysilane (EPMS) and vinyltrimethoxysilane (VTMS) in acidic conditions is proposed. Interestingly, the EV primer exhibits exceptional reactivity, self-healing capabilities, and strong adhesion to various substrates, including metals, plastics, and glass. The bonding aluminum plates are easily debonded by immersion in water without any residue left. Subsequently, the EV primer has been applied to the interface between silicone leather and the PDMS composite. Results show that the bonding strength for the silicone leather coated with the EV/PDMS composite is 16 times higher than that of the silicone leather modified with the PDMS composite. Meanwhile, the modified silicone leather exhibits impressive antifouling performance, including aqueous and oily stains, appreciable breathability, and excellent wear resistance, even if suffering from 20 000 cycles of abrasion. These excellent advantages for the modified silicone leather should be attributable to the synergistic effect of the EV primer and the PDMS composite. These findings pave the way to develop an ecofriendly debonding primer for PDMS composites, greatly facilitating applications of silicone leather.

Enhancement of thermal conductivity in PDMS/CFP composites using a dredging-plugging thermal network

In the preparation of thermally conductive polymer composites (TCPC), it is necessary to incorporate a filler network in the polymer matrix. Further enhancement of the thermal conductivity (TC) of TCPCs is challenging due to the exceptional heat absorption of the polymer matrix, which results in heat flow losses in the network. To address this issue, a novel procedure, termed thermal network dredging-plugging, has been proposed. In this study, polydimethylsiloxane (PDMS) composites with a carbon fiber powder (CFP) network and a CFP/glass ball (GB) network enhanced by dredging-plugging were prepared by a coating method. The TC of the PDMS/CFP system increased with an increase in CFP loading from 0 to 12 wt% and a decrease in sample thickness from 0.4 to 0.2 mm. At a 12 wt% CFP loading, the PDMS/CFP composites exhibited a maximum TC of 4.687 W/(mK). With the addition of GBs ranging from 0 to 2 wt%, the dredging-plugging CFP/GB network increased the maximum TC by a factor of 1.26 relative to the dredged CFP network. In conjunction with the thermal resistance method, a mathematical model that considers both the plugging and dilution effects of GBs was constructed. The calculated TCs were validated by using the prepared PDMS/CFP/GB composites, with average absolute relative errors ranging from 0.5 % to 4.19 %. In addition to TC enhancement, the mechanical properties and thermal management of the PDMS composites were evaluated.

Contribution to the percolation threshold study of Silicon carbide filled polydimethylsiloxane composites used for field grading application

The correlations between the electrical behavior and microstructural properties of samples consisting of particle composites fabricated from SiC particles embedded in a silicone matrix, were investigated using X-ray computed tomography. In the voltage field range 200-1000 V/mm, the measured conductivity as a function of SiC volume fraction exhibits two distinct gaps. Upon further investigations, we attribute these observations to percolation thresholds at the microscale. The first gap, corresponding to interconnections between SiC particles that were originally disconnected, is more significant at higher voltage; while the second one, resulting from shortening conductivity pathways between the external surfaces of the samples with the increase of SiC volume fraction, seems more sensitive to lower voltages and is correlated with a decrease of the tortuosity of the percolated SiC network.

Environmentally Friendly High‐Performance Polydimethylsiloxane Composites Reinforced with Renewable Cellulose Nanocrystals Based on Dynamic Silyl Ether Linkages

AbstractEnvironmentally friendly high‐performance composites made from either reprocessable polymer matrix or renewable fillers have become increasingly significant in order to reach a sustainable future. Herein, polydimethylsiloxane/modified cellulose nanocrystals (PDMS/mCNC) composites showing outstanding mechanical and reprocessable properties via silyl ether linkages are prepared. With only 1 wt% mCNC, the PDMS/mCNC composite exhibits the tensile strength of 2.96 MPa, which is twice that of the pure PDMS elastomer, while the toughness can achieve 7.32 MJ m−3. Remarkably, the reprocessing efficiency can be as high as 100% even for triple reprocessing process. Additionally, the favorable effect of mCNC on constructing hybrid filler network within vitrimers is explored for the first time. Selection of boron nitride nanosheet (BNNS) as the functional filler, 40 wt% BNNS is uniformly dispersed by only a small amount of mCNC and a homogeneous thermally conductive network is built, with the thermal conductivity of the PDMS/mCNC@BNNS composite increasing remarkably to 2.901 W m−1 K−1. In a word, this work paves the way to develop sustainable, mechanically strong, and reprocessable composites with mCNC as a renewable bio‐filler.

Comprehensive Investigation of the Temperature-Dependent Electromechanical Behaviors of Carbon Nanotube/Polymer Composites.

The performances of flexible piezoresistive sensors based on polymer nanocomposites are significantly affected by the environmental temperature; therefore, comprehensively investigating the temperature-dependent electromechanical response behaviors of conductive polymer nanocomposites is crucial for developing high-precision flexible piezoresistive sensors in a wide-temperature range. Herein, carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composites widely used for flexible piezoresistive sensors were prepared, and then the temperature-dependent electrical, mechanical, and electromechanical properties of the optimized CNT/PDMS composite in the temperature range from -150 to 150 °C were systematically investigated. At a low temperature of -150 °C, the CNT/PDMS composite becomes brittle with a compressive modulus of ∼1.2 MPa and loses its elasticity and reversible sensing capability. At a high temperature (above 90 °C), the CNT/PDMS composite softens, shows a fluid-like mechanical property, and loses its reversible sensing capability. In the temperature range from -60 to 90 °C, the CNT/PDMS composite exhibits good elasticity and reversible sensing behaviors and its modulus, resistivity, and sensing sensitivity decrease with an increasing temperature. At room temperature (30 °C), the CNT/PDMS composite exhibits better mechanical and piezoresistive stability than those at low and high temperatures. Given that environmental temperature changes have significant effects on the sensing performances of conductive polymer composites, the effect of ambient temperature changes must be considered when flexible piezoresistive sensors are designed and fabricated.