Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Their growth and mechanical interlocking over time are the most significant factors in shaping the material properties of concrete. The outstanding chemical and physical properties of nanomaterials provide the most efficient enhancement for the internal matrix of concrete, and recent progress in nanomodification of cement composite materials has enabled applications in structural reinforcement, reduction of environmental pollution, [2] and production of self-cleaning materials. [3] Previous studies [4][5][6][7][8][9][10] have largely focused on the incorporation of nanomaterials in cement. These include the incorporation of carbon nanotubes (CNTs) [7] and graphene oxide (GO) [4,5] in cement which resulted in a 50% (for CNT) and a 33% (for GO) improvement of the compressive strength, while industrial-grade thin graphite platelets (100 nm thickness) [6] were shown to improve the thermal conductivity. However, these findings do not extend directly to concrete, as the addition of sand and aggregate changes the physico-mechanical behavior of the material. Moreover, to date the role of atomically thin materials on nanoengineering of concrete is yet to be explored, and this holds the promise to change the landscape of construction materials leading to a more sustainable urbanization with lower carbon foot print and more resilient constructions against natural disasters.Here we report innovative few-atoms-thin graphene-enabled nanoengineered multifunctional concrete composites which display an unprecedented range of enhanced properties compared to standard concrete. We demonstrate an extraordinary increase of up to 146% in the compressive strength, up to 79.5% in the flexural one, and a decrease in the maximum displacement due to compressive loading by 78%. At the same Nanoegineered Concrete
Transparent and flexible electrodes are widely used on a variety of substrates such as plastics and glass. Yet, to date, transparent electrodes on a textile substrate have not been explored. The exceptional electrical, mechanical and optical properties of monolayer graphene make it highly attractive as a transparent electrode for applications in wearable electronics. Here, we report the transfer of monolayer graphene, grown by chemical vapor deposition on copper foil, to fibers commonly used by the textile industry. The graphene-coated fibers have a sheet resistance as low as ~1 kΩ per square, an equivalent value to the one obtained by the same transfer process onto a Si substrate, with a reduction of only 2.3 per cent in optical transparency while keeping high stability under mechanical stress. With this approach, we successfully achieved the first example of a textile electrode, flexible and truly embedded in a yarn.
self-powered electronics for which novel high-performance materials and low-cost fabrication processes are highly sought. Graphene, which exhibits remarkably high specific surface area, thermal conductivity, current density, transparency, and impermeability, [1] is an ideally suited system for exploring conceptually novel flexible electronics including energy harvesting devices. [2] An easy and scalable approach for graphene preparation is the liquid-phase exfoliation of chemically functionalized graphite, such as graphite oxide or graphite intercalated compounds, which allows the separation of the bulk material into individual atomically thin layers in a liquid medium to produce graphene suspensions. However, there are several issues associated with the films deposited from such suspensions, especially those comprising graphene oxide (GO): they are insulating and need to be converted into reduced graphene oxide (rGO) through harsh chemical or thermal processes, [3] which creates defects in the crystallographic structure of graphene, leading to poor electronic performance. Alternatively, pristine graphite (PG) can be directly exfoliated by various techniques such as ball or three-roll milling, sonication, and high-shear mixing to obtain graphene suspensions. [4,5] Such suspensions are stabilized by using organic solvents, [6] or surfactants to prevent reaggregation of the graphene flakes. [7] In particular, PG exfoliation by highshear mixing leads to a significant improvement in the quality of graphene, when compared with other exfoliation methods, and allows the production of more than 100 L h −1 of defect-free graphene water-based suspension. [5,8] Despite the recent developments in the production of graphene suspensions, the integration of high-quality graphene films obtained from water-based exfoliation of PG in emerging applications, such as flexible electronics, is lagging behind. Specifically, emerging and integrating technologies of water-based exfoliation of PG for haversting human energy that convert mechanical energy into electricity using various effects are still in its infacty, and more research is needed to develop and implement triboelectric nanogenerators (TENGs) as self-charging devices for flexible and wearable electronics. This is due to several issues associated with the deposition Wearable technologies are driving current research efforts to self-powered electronics, for which novel high-performance materials such as graphene and low-cost fabrication processes are highly sought.The integration of highquality graphene films obtained from scalable water processing approaches in emerging applications for flexible and wearable electronics is demonstrated. A novel method for the assembly of shear exfoliated graphene in water, comprising a direct transfer process assisted by evaporation of isopropyl alcohol is developed. It is shown that graphene films can be easily transferred to any target substrate such as paper, flexible polymeric sheets and fibers, glass, and Si substrates. By combining gra...
The true integration of electronics into textiles requires the fabrication of devices directly on the fibre itself using high-performance materials that allow seamless incorporation into fabrics. Woven electronics and opto-electronics, attained by intertwined fibres with complementary functions are the emerging and most ambitious technological and scientific frontier. Here we demonstrate graphene-enabled functional devices directly fabricated on textile fibres and attained by weaving graphene electronic fibres in a fabric. Capacitive touch-sensors and light-emitting devices were produced using a roll-to-roll-compatible patterning technique, opening new avenues for woven textile electronics. Finally, the demonstration of fabric-enabled pixels for displays and position sensitive functions is a gateway for novel electronic skin, wearable electronic and smart textile applications.
Graphene-coated polypropylene (PP) textile fibers are presented for their use as temperature sensors. These temperature sensors show a negative thermal coefficient of resistance (TCR) in a range between 30 and 45 °C with good sensitivity and reliability and can operate at voltages as low as 1 V. The analysis of the transient response of the temperature on resistance of different types of graphene produced by chemical vapor deposition (CVD) and shear exfoliation of graphite (SEG) shows that trilayer graphene (TLG) grown on copper by CVD displays better sensitivity due to the better thickness uniformity of the film and that carbon paste provides good contact for the measurements. Along with high sensitivity, TLG on PP shows not only the best response but also better transparency, mechanical stability, and washability compared to SEG. Temperature-dependent Raman analysis reveals that the temperature has no significant effect on the peak frequency of PP and expected effect on graphene in the demonstrated temperature range. The presented results demonstrate that these flexible, lightweight temperature sensors based on TLG with a negative TCR can be easily integrated in fabrics.
Conducting fibres are essential to the development of e-textiles. We demonstrate a method to make common insulating textile fibres conductive, by coating them with graphene. The resulting fibres display sheet resistance values as low as 600 Ωsq−1, demonstrating that the high conductivity of graphene is not lost when transferred to textile fibres. An extensive microscopic study of the surface of graphene-coated fibres is presented. We show that this method can be employed to textile fibres of different materials, sizes and shapes, and to different types of graphene. These graphene-based conductive fibres can be used as a platform to build integrated electronic devices directly in textiles.
Exciton diffusion is at the heart of most organic optoelectronic devices' operation, and it is currently the most limiting factor to their achieving high efficiency. It is deeply related to molecular organization, as it depends on intermolecular distances and orbital overlap. However, there is no clear guideline for how to improve exciton diffusion with regard to molecular design and structure. Here, we use single-crystal charge-transfer interfaces to probe favorable exciton diffusion. Photoresponse measurements on interfaces between perylenediimides and rubrene show a higher photocurrent yield (+50%) and extended spectral coverage (+100 nm) when there is increased dimensionality of the percolation network and stronger orbital overlap. This is achieved by very short interstack distances in different directional axes, which favors exciton diffusion by a Dexter mechanism. Even if the core of the molecule shows strong deviation from planarity, the similar electrical resistance of the different systems, planar and nonplanar, shows that electronic transport is not compromised. These results highlight the impact of molecular organization in device performance and the necessity of optimizing it to take full advantage of the materials' properties.
The seamless incorporation of electronics in textiles have the potential to enable various applications ranging from sensors for the internet of things to personalised medicine and human-machine interfacing. Graphene electronic textiles are a current focus for the research community due to the exceptional electrical and optical properties combined with the high flexibility of this material, which makes it the most effective strategy to achieve ultimate mechanical robustness of electronic devices for textile integrated electronics. An efficient way to create electronic textiles is to fabricate devices directly on the fabric. This can be done by coating the textile fabric with graphene to make it conductive. Here we discuss successful and efficient methods for coating graphene nanoplatelets on textile substrates of nylon, polyester and meta-aramid using ultrasonic spray coating technique. These coatings are characterised by scanning electron microscopy, contact angle and electrical conductivity measurements in order to identify the optimal textile electrode. Our study provides the foundation for the large-area fabrication of graphene electronic textiles.
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