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The integration of self-sensing and damage detection mechanisms is a critical task towards enhancing reliability of epoxy-based structures. Herein, epoxy/MoS 2 composites with various MoS 2 loadings were used as self-sensing materials for the first time in the literature. A three roll mill (TRM) was employed to exfoliate and disperse MoS 2 in-situ in the epoxy resin. The morphology and dispersion of MoS 2 nanoplatelets were examined by scanning electron microscopy. The incorporation of MoS 2 not only improved the elastic modulus of epoxy resin but also endowed the resin with enough electrical conductivity to achieve self-sensing properties. The composites exhibited gauge factors of 48, 44 and 40 when reinforced with 1.89, 2.4 and 2.93 vol% MoS 2 under tension. These gauge factors are higher than the ones reported from carbon material-reinforced epoxy composites. The semiconducting nature and 2D nanoplatelet-like structure of MoS 2 flakes are key parameters for the high sensitivity of the final composites. [Display omitted] • Epoxy/MoS 2 composites with various MoS 2 loadings were used as self-sensing materials for the first time in the literature. • The use of MoS 2 endowed epoxy with higher elastic modulus and self-sensing capability. • The MoS 2 /epoxy composites exhibited higher gauge factors than the ones reported from carbon material-reinforced epoxy composites. • The semiconducting nature and 2D nanoplatelet-like structure of MoS 2 flakes are key parameters for the high sensitivity of the final composites. [ABSTRACT FROM AUTHOR]

Abstract: The development of new flexible and stretchable sensors addresses the demands of upcoming application fields like internet‐of‐things, soft robotics, and health/structure monitoring. However, finding a reliable and robust power source to operate these devices, particularly in off‐the‐grid, maintenance‐free applications, still poses a great challenge. The exploitation of ubiquitous temperature gradients, as the source of energy, can become a practical solution, since the recent discovery of the outstanding thermoelectric properties of a conductive polymer, poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Unfortunately the use of PEDOT:PSS is currently constrained by its brittleness and limited processability. Herein, PEDOT:PSS is blended with a commercial elastomeric polyurethane (Lycra), to obtain tough and processable self‐standing films. A remarkable strain‐at‐break of ≈700% is achieved for blends with 90 wt% Lycra, after ethylene glycol treatment, without affecting the Seebeck voltage. For the first time the viability of these novel blends as stretchable self‐powered sensors is demonstrated. [ABSTRACT FROM AUTHOR]

Two graphene-based nanofillers of different sizes were melt mixed with polylactide acid (PLA). Composite films based on graphite nanoplatelets (GNPs) with the largest lateral size showed superior electrical conductivity and a lower percolation threshold after melt-compounding and hot-pressing at room temperature. However, upon annealing in the melt, composites based on GNPs with the smallest lateral size displayed significantly improved electrical conductivity and a decrease in percolation threshold as a result of dynamic percolation while composites based on large GNPs showed hardly any change in conductivity and percolation threshold. Hybrid filler systems based on 5 wt% GNP with variable small/large GNP filler ratios displayed synergistic effects in the formation of a conductive network during thermal annealing, and an optimum filler ratio of 50/50 was found to achieve the highest conductivity after annealing. This annealing-induced increase in particle connectivity for composites based on 5 wt.% hybrid small/large GNPs was also reflected in rheological measurements by the manifestation of a plateau in the storage modulus at low frequencies after annealing while such phenomenon was not observed for nanocomposites solely based on either small or large GNPs at similar loadings. [ABSTRACT FROM PUBLISHER]

Oriented poly(lactic acid) (PLA)/multiwall carbon nanotube (MWNT) tapes are prepared by solid-state drawing. These tapes showed significant morphological, mechanical and electrical property changes after drawing, with polymer crystallinity, nanotube dispersion and alignment being improved. Interestingly, the presence of the MWNTs perturbed the orientation of the crystalline polymer chain domains. Drawing lowered the electrical conductivity and increased the percolation threshold of the nanocomposites, but micromechanical analysis showed that it greatly improved the reinforcing efficiency of the MWNTs. This resulted in an overall good balance with one of the best compromises in terms of high mechanical properties and electrical properties for conductive polymer composite tapes. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the electrical properties of ternary nanocomposites based on thermoplastic polyurethane (TPU) and multi-walled carbon nanotubes (MWCNTs) are studied. In particular two nanofillers – differing in shape and electrical properties – are used in conjunction with MWCNTs: an electrically conductive CB and an insulating needle-like nanoclay, sepiolite. The ternary nanocomposites were manufactured in a number of forms (extruded pellets, filaments and compression moulded films) and their morphological and electrical properties characterised as function of time and temperature. The presence of both secondary nanofillers is found to affect the formation of a percolating network of MWCNTs in TPU, inducing a reduced percolation threshold and tuneable strain sensing ability. These ternary nanocomposites can find application as conductive and multi-functional materials for flexible electronics, sensing films and fibres in smart textiles. [Copyright &y& Elsevier]

Abstract: A new concept is described that creates highly oriented multifunctional polymer nanocomposite tapes (or fibres) that combine high stiffness and strength with good electrical properties and a low percolation threshold of conductive nanofillers. The concept is based on a bicomponent construction consisting of a highly oriented polymer core together with conductive polymer composite skins based on a polymer with lower melting temperature than the core. This construction allows for a thermal annealing process that can be applied selectively to the skins to improve their conductivity through a kinetic re-aggregation process while retaining the mechanical properties of the core and hence those of the overall tape or fibre. In the current study this generic concept was applied to bicomponent tapes based on a polypropylene homopolymer core and a multi-wall carbon nanotube or carbon black filled polypropylene copolymer skin. The conductivity of the bicomponent tape containing 5.3wt.% of MWNTs in its outer skins increased from 1.3E−6 to 1.5S/cm after annealing while the percolation threshold in the copolymer skins of highly drawn bicomponent tapes could be decreased from 5.3 to 1.1wt.%. To the best of the authors’ knowledge this is the lowest percolation threshold reported in literature for highly drawn polymer nanocomposites fibres or tapes. In fact, the percolation threshold is as low as 0.1wt.% when considered on the overall tape as the conductive skins account for only 10% of the total volume of these bicomponent tapes. [Copyright &y& Elsevier]

Developing materials for electronics and sensing based on abundant and degradable materials is fundamental for transitioning both fields toward a more sustainable future. In the long run, this approach can unleash these fields from using petroleum‐derived and/or scarce resources, possibly facilitating electronic waste (e‐waste) management at the same time. Starch, one of the most abundant and versatile natural polymers, has shown great potential in the fabrication of degradable/transient devices. In this work, electrically conductive and mechanically robust starch‐Ti3C2Tx MXene nanocomposites are successfully engineered, offering a promising advancement in sustainable electronics. The nanocomposite films exhibit remarkable tunability with varying MXene concentrations (from 0.69 to 2.42 vol%), allowing precise control over their properties. This tunability enables modifications in tensile strength (from 6.4 to 11.2 MPa), electrical conductivity (from 2.31 × 10−3 to 3.98 S m−1), and gauge factor. Such characteristics make these films ideal for various applications, including body movement monitoring, tactile sensing, handwriting recognition, and electronic smart skin. Unlike their petroleum‐based counterparts, the starch‐based films demonstrate significant biodegradability, breaking down within a month after being buried in soil. This rapid degradation highlights the potential of these transient composites for various electronics applications, offering an environmentally friendly alternative. [ABSTRACT FROM AUTHOR]

In this work, a new type of carbon fiber reinforced polymer (CFRP) composite was fabricated by introducing MXene nanoparticles onto the surface of carbon fibers (CF) via electrophoretic deposition (EPD) followed by thermal annealing. The MXene-reinforced CF/epoxy composites displayed enhanced mechanical properties and electrical conductivity as well as in-situ damage sensing capability. The uniformly deposited MXene nanoparticles contributed to a considerable enhancement of the flexural strength of CFRPs through hydrogen bonding and mechanical interlocking. The thermal annealing treatment reduced the amount of oxygen groups on the surface of MXene nanoparticles and enabled a 66 % increase of the out-of-plane electrical conductivity and a 20 % improvement of the electromagnetic interference (EMI) shielding effectiveness. The exceptional EMI performance of the core-shell hierarchical microstructure can be ascribed to the polarization of the inhomogeneous interfaces, the dipole polarization, and the conductive loss effect as a result of the presence of annealed MXenes on the surface of CFs. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract The network formation of reduced graphene oxide (rGO) within an epoxy resin during curing has been in-situ visualised for the first time, with its effect on electrical, mechanical, and multifunctional properties of these nanocomposites explored. Different initial states of dispersion and filler contents were employed to examine the nanofiller network formation process. Good electrical conductivity (10−3 S/m at 0.05 wt% rGO) together with good mechanical reinforcement (12% increase in flexural modulus at 0.2 wt% rGO) were obtained at relatively low filler loadings. The integrated strain sensing capabilities based on the rGO network were explored with good sensitivity and repeatability. Joule heating was performed as a potential application for de-icing of multifunctional composite components with good heating capability from −20 °C to 20 °C within 2 min. [ABSTRACT FROM AUTHOR]