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Printed conductive polymer composites allow for the bespoke manufacture of products with complicated geometries, which is critical for rapid prototyping and adaptability of flexible electrical devices. However, it is still challenging to prepare environmentally friendly and sustainable conductive polymer composites with aqueous solvent systems which accomplish excellent printing and electromechanical properties at the same time. In this work, the effect of composite components on performance was explored, and orthogonal tests were utilized to discover the precise formulation of new green aqueous conductive polymer composites with superior performance. The printing accuracy of the conductive polymer composites was enhanced (printed circuit burrs less than 20 μm) and the dependability of the printed circuits as well as the failure mechanism during electrochemical migration (ECM) were thoroughly investigated. As a proof of concept, ultrahigh frequency (UHF) flexible linearly polarized antennae with read range forward surpassing 10 m was designed and printed. [ABSTRACT FROM AUTHOR]

Highlights: The paper introduces a bioresorbable elastomer, poly(glycolide-co-ε-caprolactone) (PGCL), with remarkable mechanical properties, including high elongation-at-break (< 1300%), resilience, and toughness (75 MJ m−3) for soft and transient electronics. Fabrication of conducting polymers with PGCL yields stretchable, conductive composites for transient electronic devices, functioning reliably under external strains. The study demonstrates the feasibility of a disintegrable electronic suture system with on-demand drug delivery for rapid recovery of post-surgical wounds on soft, time-dynamic tissues or versatile biomedical areas of interest. Substrates or encapsulants in soft and stretchable formats are key components for transient, bioresorbable electronic systems; however, elastomeric polymers with desired mechanical and biochemical properties are very limited compared to non-transient counterparts. Here, we introduce a bioresorbable elastomer, poly(glycolide-co-ε-caprolactone) (PGCL), that contains excellent material properties including high elongation-at-break (< 1300%), resilience and toughness, and tunable dissolution behaviors. Exploitation of PGCLs as polymer matrices, in combination with conducing polymers, yields stretchable, conductive composites for degradable interconnects, sensors, and actuators, which can reliably function under external strains. Integration of device components with wireless modules demonstrates elastic, transient electronic suture system with on-demand drug delivery for rapid recovery of post-surgical wounds in soft, time-dynamic tissues. [ABSTRACT FROM AUTHOR]

In order to prepare a flexible strain sensor with a large monitoring range, high sensitivity and excellent stability, a polyolefin elastomer (POE)/carbon nanotubes (CNTs) conductive polymer composite with a bilayer structure was prepared by biaxially stretching in this work. The results showed that the bilayer structured nanocomposites had better processability and better stability than monolayer CNT/POE nanocomposites during biaxial stretching. The biaxial stretching process could promote the dispersion and planar orientation of CNTs within the polymer, improving the crystallinity of nanocomposites and the sensing performance of strain sensors. The optimal stretching ratios (SRs) of bilayer structured nanocomposites were studied. The 8 wt% CNT/POE‐POE strain sensor with an SR of 2.5 exhibited a high sensitivity (gauge factor/GF = 72604.7 at 900% strain), wide strain range (0%–900%), and stable cycling performance (1000 cycles at 30% strain), showing a broad application prospect in wearable electronic devices. This study provides a valuable method for efficiently manufacturing high performance and low‐cost flexible strain sensors. [ABSTRACT FROM AUTHOR]

The magnesium oxide–nickel oxide (MgO–NiO), nickel oxide–cobalt oxide (NiO–CoO), and magnesium oxide–cobalt oxide (MgO–CoO)-based mixed metal oxides (MMO) were synthesized by sol–gel method. The grafting of conductive polymers (CP), namely polyaniline (PANI), polyorthoanisidine (POA), and PANI–POA copolymer, is carried out on synthesized mixed metal oxide (MMO) by using a chemical oxidation method using ammonium persulfate (APS) as oxidizer, and the doping agent is used as hydrochloric acid (HCl) to make the MMO-CP composites. The synthesis of MMO-CP formation was confirmed with the FTIR, XRD, and UV–visible analysis. The epoxy-polyamide coating formulation is reinforced with MMO-CP composites at 4% (w/w) concentration, and the ultrasonication technique is used for uniform dispersion of MMO-CP into the coating formulation. The mild steel is used as a substrate for casting synthesized coating film, and curing is carried out at 90 °C. The mechanical analysis observed that hardness properties and scratch formation resistance are increased by reinforcement of MMO-CP, whereas chemical resistance remained unaffected. The corrosion resistance increased by incorporation of MMO-CP into the coating formulation, and it is evaluated by the salt spray analysis. The NiO–CoO–POA composite-based coating performs excellently in pencil hardness, scratch resistance, and in the salt spray test. [ABSTRACT FROM AUTHOR]

Conductive polymer composites (CPCs) have been identified as viable replacements for graphite and metals for polymer electrolyte membrane fuel cell (PEMFC) bipolar plates (BPs). One important factor, apart from composite formulation, that affects the quality and properties of CPC BPs is the processing route. Therefore, understanding the possible processing methods for different matrix–filler combinations and their effects on the quality and properties of the plates can help in controlling and improving the final performance of BPs. This paper reviews the blending and molding techniques for CPC BPs, with a focus on relationship between formulation and processing method. The effects of processing route and conditions on microstructural features of CPC BPs, which affect the performance of the plates are also discussed. Finally, directions for further studies with potential to advance the development of quality and high‐performance CPC BPs are highlighted. Identified key areas for further research include control of filler orientation to improve through‐plane conductivity, correlation between processing parameters and dimensional accuracy of molded plates, and additive manufacturing of composite BPs. [ABSTRACT FROM AUTHOR]

Conductive polymer composites (CPCs) have demonstrated significant potential in the aerospace, electronics, and communications industries. In this study, polypropylene (PP)/multiwalled carbon nanotubes (MWCNTs) binary composites and in situ fiber reinforced multicomposites made from PP/MWCNTs were fabricated by microcellular injection molding. In addition to crystallization behavior, foam morphology, mechanical properties, dielectric properties, and electromagnetic shielding properties of the composites were analyzed. According to the results, microporous structures can facilitate the distribution of conductive fillers, thereby enhancing the electromagnetic shielding performance and mechanical properties of the composite. In situ microfiber networks display a heterogeneous nucleation effect, resulting in an increase in foam density, which improves composite performance. In situ fiber‐reinforced microporous multicomposites are capable of exhibiting higher elongation at break and electromagnetic shielding properties than binary systems, and the multicomposites can achieve greater electromagnetic shielding effectiveness (SE) with fewer conductive fillers. Ultimately, fiber‐reinforced microporous composites with an elongation at break of 194.40%, an electromagnetic shielding effect of >20 dB, and an absorption mechanism are produced. A feasible method is presented in this study for preparing CPCs that produce light weight, excellent mechanical properties, and high electromagnetic SE at low filler levels. [ABSTRACT FROM AUTHOR]

Four-dimensional (4D) printing technology is an innovative concept integrating conventional 3D printing additive manufacturing (AM) and smart materials programed to change properties or shape over time in response to environmental stimuli. This study aims to characterize the strength and electrical resistance of a commercial electrically conductive polylactic acid (PLA) with carbon black (CB) particles printed by fused filament fabrication (FFF) technique to evaluate the development feasibility of two sensor prototypes: (1) a load-cell sensor, and (2) a temperature sensor. Experiments were performed to study the orientation and raster angle--dependent mechanical and electrical performance of a PLA-CB conductive polymer manufactured by AM-FFF technology. A good agreement was observed between the data received from the manufacturer and the experimental density of the conductive AM-FFF PLA-CB three-point bending samples. The mechanical properties of 3D-printed PLA-CB were characterized based on three-point bending flexural test. Two build orientations (flat and upright) and three raster patterns (0°/90°, +45°/-45°, and concentric) were printed to check the optimal mechanical properties for electrical conductivity; six samples were printed for each one of the six configurations. The three-point bending flexural test results of the examined 36 specimens demonstrated that the samples printed in the concentric and +45°/-45° raster patterns exhibit the best mechanical properties, with the highest flexural strength and flexural modulus of elasticity in the flat orientation. Nevertheless, the concentric pattern has an advantage over the +45°/-45° pattern due to higher density and homogeneity. To examine the electrical resistance of the PLA-CB material another 12 specimens were printed and divided into four groups, each with different lengths. The electrical intrinsic resistivity was calculated from the geometry of the specimens and the measured resistance, with an average value of 13.2 [Ω·cm]. To check the production feasibility of a load-cell sensor prototype the effect of load on electrical conductivity was examined, however no effect of load on resistance was discovered. To prove the production feasibility of a sensor prototype for temperature measurements a preliminary device was designed and the effect of increasing and decreasing the temperature between 24 and 42°C on electrical resistance was examined. Based on the experimental results a calibration function was built linking between the temperature and the material's resistance. [ABSTRACT FROM AUTHOR]

Thermally and electrically conductive polymer composites (CPCs) have been widely used in smart and flexible electronics; however, huge challenges remain in simultaneously improving the electrical and thermal conductivity of CPCs while maintaining the satisfactory mechanical properties including sufficient strength and toughness. In this study, we propose an effective interfacial regulation approach to fabricate CPCs with a dual conductive network through decoration of Ag nanoparticles (AgNPs) onto the polyurethane (PU) nanofibers containing graphite nanoplatelets (GNPs), followed by hot-pressing. Rigid GNPs expand the PU nanofiber network, facilitating Ag precursor adsorption, while subsequent hot-pressing eliminates the big channels and pores inside nanofiber composite membranes and hence greatly enhance their mechanical properties. After hot-pressing, the synergistic dual conductive network with greatly reduced thermal and electrical contact resistance leads to significant improvements in both thermal and electrical conductivity (up to 27.71 W (m K)−1 and 1.87 × 106 S/m, respectively). Moreover, the mechanically robust CPCs with exceptional durability possess superior Joule heating performance at low voltages and heat dissipation capability. This study provides inspiration for designing highly thermally and electrically conductive CPCs with potential applications as flexible thermal interface materials. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, flexible piezoresistive strain sensors of carbon nanotubes (CNT)/thermoplastic polyurethane (TPU) conductive polymer composites were prepared using fused filament fabrication (FFF) 3D printing. The constructed porous structure and highly elastic TPU matrix allow the sensors to experience strains up to 30% with great recoverability. The printed sensors exhibited a typical negative piezoresistive effect under compressive strain. The effects of non-covalent modification and loading of CNTs on the mechanical and piezoresistive behavior of sensors were investigated. The introduction of 1-pyrenecarboxylic acid (PCA) increased the dispersibility of CNTs and nanofiller-polymer interfacial interactions, resulting in the excellent sensing performance. A sensor with higher CNT content showed greater sensitivity due to generation of more conductive paths during compression. The gauge factor ( G F) of the 3 wt% CNT/PCA/TPU sensor increased by 43 and 35 times compared with the 3 wt% CNT/TPU and the 1.5 wt% CNT/PCA/TPU sensors, respectively, when strained at 26% to 30%. In addition, the printed sensor of 3 wt% CNT/PCA/TPU showed great reproducibility over 1500 loading cycles. Some applications in monitoring external loads and motion of the human body were demonstrated. This work provides important information for the property optimization and customizable fabrication of flexible piezoresistive strain sensors. [ABSTRACT FROM AUTHOR]

Conductive polymer nanocomposites (CPC) are considered to be one of the best materials for the various applications like sensors, electrolyte membrane, photovoltaic cell, electromagnetic interference shielding materials, overcurrent protection devices, and many more due to the balance between electrical and mechanical properties, low cost, and ease of manufacturing. The most important aspect of an electro‐CPC is the interface between the polymer and conductive filler. In order to be electro‐conductive the fillers need not be in physical contact between them rather a few nanometer (typically ~10 nm) gap exist between two neighboring filler. Electrical conductivity of the composites arises from electron tunneling and hopping between conducting network. A typical way of preparing polymeric nanocomposites is the direct incorporation of inorganic nanoparticulate filler into polymers. Primarily focus has been given to carbonaceous nanoparticles in this article. Nanoparticles are an automatic choice for preparing the nanocomposites owing to their high‐interfacial interaction. However, it is often very difficult to well disperse nanoparticles in polymers because the nano particles with high‐surface energy are easy to agglomerate, which in turn adversely affects electron conduction in nanocomposites. One of the most used techniques to overcome this difficulty is to modify the interface of the polymer and filler as often the interface between polymer and filler played a crucial role in electron conduction. The aim of this review article is to report the most recent developments in improving the interface of filler and polymers in CPC. The discussions are primarily focused on different methodologies for the preparation of CPC characterization of the interface and finally interface modification techniques. [ABSTRACT FROM AUTHOR]

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Conductive polymer composites (CPCs) consisting of polymer materials and conductive nanofillers have excellent flexibility, ease of processing, as well as excellent mechanical and electrical properties, resulting in an enormous application potential in flexible strain sensors and other fields. In this paper, a flexible strain sensor consisting of an ethylene–vinyl acetate (EVA) copolymer/carbon nanotube (CNT) CPC with a bilayer structure was prepared by biaxial stretching. The results indicated that the conductivity of the composites gradually decreased as the stretching ratio (SR) increased, due to the major destruction to the conductive network caused by biaxial stretching. Biaxial deformation facilitates the dispersion and in-plane alignment of CNTs, thereby enhancing the property of the sensor. Compared with the unstretched CNT/EVA-EVA-1.0 bilayer-structured sensor [gauge factor (GF) = 89.4, monitoring range 0.5–50%], the CNT/EVA-EVA-1.5 bilayer-structured sensor (SR = 1.5) after biaxially stretched exhibited higher sensitivity (GF = 349698.2) and a wider strain monitoring range (0.5–120%). In addition, compared with monolayer CNT/EVA sensors, the bilayer-structured sensors exhibited higher stability, highlighting their good application prospects in health monitoring in the field of artificial intelligence. [Display omitted] • Bilayer-structured strain sensor was prepared by biaxial stretching (BS). • The stability of bilayer-structured nanocomposite was higher than monolayer. • BS improved the sensor performance due to enhanced CNT dispersion and orientation. • The sensor showed a wide detectable range (0.5–120%) and high sensitivity (GF=349698.2). [ABSTRACT FROM AUTHOR]

A versatile networking method is reported for conductive polymer/carbon black (CB) composites on the basis of simultaneous dispersion and interaction-induced network assembly during melt compounding via addition of a very small amount (about 1 wt%) of secondary polymer that has stronger interaction with CB than the matrix polymer. Four different systems including polyamide 6 (PA6)-modified polycarbonate (PC)/CB, thermoplastic polyurethane (TPU)-modified polyoxymethylene (POM)/CB, PA6-modified POM/CB and TPU-modified polypropylene (PP)/CB composites were investigated to demonstrate the feasibility of the method. 1 wt% secondary polymer can effectively induce assembly of CB particles, forming higher-structure loosely-packed agglomerates. Even with 0.3 wt% secondary polymer, the percolation threshold could decrease by 30%. The mechanism for the hierarchical morphology of filler arrangement is proposed on the basis of preferential wetting and infiltration of CB by secondary polymer and the assembly of dispersed CB aggregates around/in the small droplets of secondary polymer. The reduced inter-agglomerate tunnelling distance and enhanced secondary electric field are proposed as the mechanisms for improved electrical conductivity. [ABSTRACT FROM AUTHOR]

Intrinsically conducting polymers (ICP) and conductive fillers incorporated conductive polymer-based composites (CPC) greatly facilitate the research in electromagnetic interference (EMI) shielding because they not only provide excellent EMI shielding but also have advantages of electromagnetic wave absorption rather than reflection. In this review, the latest developments in ICP and CPC based EMI shielding materials are highlighted. In particular, existing methods for adjusting the morphological structure, electric and magnetic properties of EMI shielding materials are discussed along with the future opportunities and challenges in developing ICP and CPC for EMI shielding applications. [ABSTRACT FROM AUTHOR]

We developed a simple analytical model to describe the instantaneous location and angle of rod-like conductive fillers as a function of cell growth during the foaming of conductive polymer composites (CPCs). First, we modelled the motion of the fillers that resulted from the growth of one cell. Then, by taking into account the fillers located at the line that connected the centres of the two growing cells, we found the final filler's angle and location. We identified this as a function of the corresponding cell size, filler size, and the filler's initial angle and location. We based the model's development on the assumption that a polymer melt is incompressible during cell growth. The two-cell growth model is better than the one-cell growth model because it describes the filler's movement in the cell wall between the two growing cells. The results revealed that the fillers near the cell were the ones most affected by the cell growth, while those at the midpoint between the two cells were the least affected. As a cell grows, its affected polymer area also increases. A dimensionless factor η was introduced to demonstrate the effects of the cell size and the filler length on the filler's interconnectivity in the CPC foams. It is vital to keep the filler length comparable to the cell size when preparing CPC foams with the desired electrical conductivity. Our research provides a deeper understanding of the mechanism through which foaming influences the filler connections in CPC foams. [ABSTRACT FROM AUTHOR]

Smart heating devices with reliable self-regulating performances and high efficiency, combined with additional properties like mechanical flexibility, are of particular interest in healthcare, soft robotics, and smart buildings. Unfortunately, the development of smart heaters necessitates managing normally conflicting requirements such as good self-regulating capabilities and efficient Joule heating performances. Here, a simple and universal materials design strategy based on a series connection of different conductive polymer composites (CPC) is shown to provide unique control over the pyroresistive properties. Hooke's and Kirchhoff's laws of electrical circuits can simply predict the overall pyroresistive behavior of devices connected in series and/or parallel configurations, hence providing design guidelines. An efficient and mechanically flexible Joule heating device is hence designed and created. The heater is characterized by a zero temperature coefficient of resistance below the self-regulating temperature, immediately followed by a large and sharp positive temperature coefficient (PTC) behavior with a PTC intensity of around 106. Flexibility and toughness is provided by the selected elastomeric thermoplastic polyurethane (TPU) matrix as well as the device design. The universality of the approach is demonstrated by using different polymer matrices and conductive fillers for which repeatable results are consistently obtained. [ABSTRACT FROM AUTHOR]

The piezoresistive effect is an important property of conductive polymer composites (CPCs), but the conductive behavior of the composite under shock wave of high pressure and high strain rate, including incident wave and reflected wave, needs to be further studied. To characterize such a system, we study the variation in electrical conductivity of a conductive polymer composite under shock waves, including loading wave and unloading wave, in this paper. The polymer matrix is polyamide-6 with carbon nanotubes and stainless steel fibers are the fillers. The data indicate that the resistivity decreases under the loading shock wave, but sharply increases due to the unloading shock wave. Scanning electron microscopy (SEM) reveals that this resistivity increase is due to damage by the unloading wave and subsequent failure of many micro-conductive channels in the material. [ABSTRACT FROM AUTHOR]

A property-induced differential structure, which includes negative temperature coefficient unit (NTCU) and positive temperature coefficient unit (PTCU), is designed to increase the sensitivity of temperature sensor based on conductive polymer composite. The composite with/without cellular structure is used as the sensitive material in NTCU/PTCU, which results in a decrease/an increase of the electrical resistance with the increase of the temperature. Through using NTCU and PTCU as the neighboring arms of an electrical bridge, the temperature is converted into a voltage. The results verify the feasibility of using the property-induced differential structure to improve the sensitivity. [ABSTRACT FROM AUTHOR]

The structure development in conductive polymer composites during deformation is a topic of great interest as the structure of conductive particle pathways governs electrical properties of the composite. In this paper simultaneous electrical and rheological measurements in elongation are introduced for the first time using a modified Münstedt tensile rheometer. Such kind of experiment can help in understanding the relationships between processing and properties of conductive polymer composites. The first results presented were obtained on polystyrene containing 4 vol.% of carbon black at the temperature of 150 °C. Similar to the shear, the conductivity development under elongation is given by a competition of flow-induced destruction and build-up of particle structures and it is considerably influenced by the strain rate applied. [ABSTRACT FROM AUTHOR]

Conductive polymer composites have generated significant academic and industrial interests in recent years. The microstructure directly affects the performances of conductive polymer composites. In this study, two structures, i.e., randomly distributed structure and 3D segregated structure, were fabricated in chlorinated polyethylene/multi-walled carbon nanotube (CPE/MWCNT) composites via solution mixing and direct hot-pressing, respectively. The morphology, electrical conductivity, mechanical property, flame resistance and rheological property of two structures were comparative studied. The results showed that the conductive paths were easier to build in 3D segregated structure. The percolation threshold of randomly distributed structure (4.81 wt%) was 4.4 times higher than that of 3D segregated structure (1.09 wt%). The addition of MWCNT enhanced the flame retardance in both two composites and the limiting oxygen indices of randomly distributed structure and 3D segregated structure with 10 wt% MWCNT were 28.7% and 26.3%, respectively. The addition of MWCNT also improved the mechanical property in both two composites, while the improvement in randomly distributed structure was remarkedly larger than that in 3D segregated structure. Besides, the rheology results proved that the interaction between MWCNTs and CPE matrix in randomly distributed structure was stronger than that in 3D segregated structure. The results are beneficial to the manufacture of conductive polymer composites with appropriate electrical conductivities, balanced mechanical properties and flame retardant properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: This paper focused on using a conductive polymer composite (CPC) as a potential replacement for the conventional graphite bipolar plate used in polymer electrolyte membrane fuel cells (PEMFC). Based on the requirements established by the US Department of Energy (DOE), the in-plane electrical conductivity and flexural strength are required to be greater than 100S/cm and 25MPa, respectively. The high filler loading is needed to satisfy the high in-plane electrical conductivity. However, the high filler loading reduces the flexural strength and manufacturability of the composite. In this study, the composites were prepared by compounding using an internal mixer followed by compression moulding. The combination of 10vol% carbon black (CB) as the second filler with synthetic graphite/epoxy (SG/EP) resulted in the following composite properties: 150S/cm (in-plane conductivity), 55S/cm (through-plane conductivity), and 38.8MPa (flexural strength). Used as the second filler, the CB, which had a small-sized diameter, formed conductive networks that filled the voids between the SG and polymer matrix. The in-plane electrical conductivity and flexural strength of the CB/SG/EP composites at the optimum composition exceeded the requirement for bipolar plate applications. [Copyright &y& Elsevier]

We evaluated a solvent vapor-sensitive, non-woven fabric made from a biodegradable, poly(lactic acid) (PLA) polymer loaded with multi-walled carbon nanotubes. The sensory properties of the fabric were obtained by optimizing the process parameters for manufacturing the melt-blown, non-woven fabric composed of 98% PLA 4060D (Nature Works) and 2% multi-walled carbon nanotubes (Nanocyl®). The diffusion of polar and non-polar solvent molecules influenced the electron flow between the separated carbon nanotubes in percolation paths built into the PLA, resulting in an increase of the resistance of the melt-blown, non-woven fabrics. The statistically significant differences between the mean values of electrical resistance before and after the influence of the tested solvent vapors were achieved for the non-woven fabrics manufactured at high air velocity and low extruder screw speed, taking the values of 30 m3/h and 20 rpm, respectively. The results obtained for the non-woven fabric manufactured in the optimal conditions show that methanol vapor response has the lowest amplitude of 15%, whereas for benzene, acetone and toluene sensitivity reaches values of 60%, 40%, and 35%, respectively. The values of the relative resistance amplitude correspond with Flory–Huggins interaction parameters κPLA\benzene < κPLA\acetone < κPLA\toluene < κPLA\methanol. [ABSTRACT FROM PUBLISHER]

Abstract: Polymer composites filled with silver nanowires enable the highest value of electrical conductivity known up to now in the case of conductive nanoparticle dispersion with a percolation threshold less than 1vol%. Silver nanowires with high aspect ratio were elaborated by two types of synthesis: electrochemical deposition in a template and polyol synthesis. For the first time the influence of each kind of nanowires in composites was studied and compared to spherical nanoparticles as reference. The value of percolation threshold and conductivity level above the percolation threshold were measured and compared. These silver nanowires were introduced into poly(vinylidenedifluoride-trifluoroethylene) in comparison to spherical silver nanoparticles. The preparation method modified the effective aspect ratio of nanowires. The low percolation threshold and the microscopy observations confirmed the good dispersion of nanowires in composites. The lowest percolation threshold was determined in the case of the polyol synthesis nanowires (0.63vol%) in comparison with electrochemical deposited nanowires (2.2vol%). The level of conductivity above the percolation threshold obtained with each kind of particles is in the same range near 100S.m−1. The value of electrical conductivity obtained above the percolation threshold is unusual at this low content of conductive filler and is observed for the first time in a conductive polymer composite. [Copyright &y& Elsevier]

Abstract: The changes in the electrical resistance of flexible pressure sensitive material based on carbon black filled silicone rubber composite during compressive creep and recovery are researched. The relation between the instantaneous increment (decrement) of the pressure and the instantaneous increment of the resistance of the composite is monotonically increasing. The resistance decreases over time after the composite is loaded to a constant pressure or unloaded to zero-pressure. The experimental data for the relative resistances during compressive creep and recovery are fitted. The final steady relative resistance in the process of compressive creep (recovery) decreases with the increase of the instantaneous pressure increment (decrement). The experimental phenomena are explained qualitatively by analyzing the changes in effective conductive paths of the composite. [Copyright &y& Elsevier]

Abstract: The aim of this work is to develop a large area thin film of a conductive polymer composite (CPC) for large area strain sensor applications. Therefore an alternative plasma deposition process is applied for the manufacturing of CPC as flexible thin films. Plasma polymer films are used as matrix that are deposited with a 60MHz plasma reactor and characterized with dynamic mechanical analyzes (DMA). Copper nanoparticles with different sizes are generated in a special hollow cathode. To enhance the sensitivity of the strain sensor a particle concentration in the matrix at the percolation threshold is important. For this reason, in situ U/I-measurements during particle deposition were done. The characteristics of resistance of the CPC films are analyzed during elongation. [Copyright &y& Elsevier]

Electrical properties of two conductive polymer composites (CPC) not yet studied in the literature, poly(amide12-b-tetramethylene oxide)-carbon black (PEBAX-CB) and poly(ethylene-co-ethyl acrylate)-carbon black (EEA-CB) in the presence of two organic solvent vapours, chloroform and toluene, have been studied as a function of processing conditions (in the melt by extrusion and from solution by casting). The experiments show that the electrical response of the CPC to solvent vapours can be modulated not only by changing the chemical nature of the polymer but also by tailoring the CPC morphology, i.e. the area accessible to solvent molecules both at a micro and nanometric scale and the conductive paths structure. For this purpose, the use of either block or statistical copolymers is interesting in achieving microphase separation or good CB dispersion, respectively. The results show on the one hand that important responses to solvent vapours ΔR/Rmax can be achieved with high conductivity samples but at the detriment of response time. On the other hand, the use of the curve shape, i.e. the diffusion mode characterised by ΔR/Rmax versus √ of t curves slope and onset, would allow us to decrease the number of CPC necessary for vapour detection. Moreover, sorption kinetic measurements show that toluene diffusivity is about two times lower in EEA-CB than in EEA. This phenomenon can be explained by a hindrance effect of the carbon black particles and a decrease of plasticization of EEA chains by toluene molecules due to interactions between EEA and CB. Therefore, the sensitivity of the CPC to solvent vapours results from conductive particles disconnection due to volume expansion during the matrix swelling. [Copyright &y& Elsevier]

Biosensors are analytical devices which find extensive applications in fields such as the food industry, defense sector, environmental monitoring, and in clinical diagnosis. Similarly, intrinsically conducting polymers (ICPs) and their composites have lured immense interest in bio‐sensing due to their various attributes like compatibility with biological molecules, efficient electron transfer upon biochemical reactions, loading of bio‐reagent, and immobilization of biomolecules. Further, they are proficient in sensing diverse biological species and compounds like glucose (detection limit ≈0.18 nm), DNA (≈10 pm), cholesterol (≈1 µm), aptamer (≈0.8 pm), and also cancer cells (≈5 pm mL−1) making them a potential candidate for biological sensing functions. ICPs and their composites have been extensively exploited by researchers in the field of biosensors owing to these peculiarities; however, no consolidated literature on the usage of conducting polymer composites for biosensing functions is available. This review extensively elucidates on ICP composites and doped conjugated polymers for biosensing functions of copious biological species. In addition, a brief overview is provided on various forms of biosensors, their sensing mechanisms, and various methods of immobilizing biological species along with the life cycle assessment of biosensors for various biosensing applications, and their cost analysis. [ABSTRACT FROM AUTHOR]