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Recent research achievements for flexible pressure sensors have promoted promising applications, such as human health detection and intelligent robotics. However, striking a balance between sensitivity and linear detection range is still a challenge. In this paper, a dual conductive layer dome (DCLD) structure, where a silver (Ag) nanowire layer is used as a highly conductive layer and the composite layer of carbon black nanoparticles and polydimethylsiloxane (CPDMS) serves as a low conductive layer, is fabricated with a scratch coating process followed by dip-coating and vacuum adsorption. Benefitting from the dual conductive layer design, the sensitivity of the DCLD sensor reaches 51.7 kPa–1 over an ultrawide pressure of 0.01–250 kPa, which is far better than the CPDMS single conductive layer dome (SCLD). The circuit models of DCLD and SCLD are proposed to disclose their working mechanism. The effects of carbon black nanoparticle ratio in CPDMS and the structural matching between the DCLD structure and electrode on the sensor's performance are explored. The long-cycle stability of DCLD sensors with different fabrication methods is also compared. Additionally, it has been demonstrated that the sensor is efficient in monitoring human motion, such as finger joint flexion, pulse pulses, and human breathing, showing potential in the field of human health monitoring. [ABSTRACT FROM AUTHOR]

A microstructured surface has been applied in self-powered triboelectric pressure sensors to increase the charge-carrying sites and enhance the output performance. However, the microstructure increases the distance between the electrode and the triboelectric layer, and its influence on the output performance is unknown. Herein, we proposed a dome-conformal electrode strategy for a self-powered triboelectric nanogenerator (TENG) pressure sensor. With a simple reverse-dome adsorption process, an ultrathin triboelectric layer and Ag electrode can be made conformal to the dome PDMS structure. The TENG sensor is constructed with paper as a positive triboelectric layer. Compared with the device based on nonconformal structure, the conformal design strategy endows the device with a faster charge transfer and enhanced output voltage. By doping with BaTiO 3 , the outermost triboelectric layer can be easily modified to improve its ability of sustaining charge, and an ultrathin PDMS layer is coated on the triboelectric layer to expand the triboelectric polarity difference between two triboelectric layers so as to enhance the output voltage. The synergistic effects enable the optimized TENG sensor with a sensitivity of 0.75 V/kPa in the low-pressure region (0-26 kPa) and 0.19 V/kPa in the high-pressure range (26-120 kPa). Its application in human motion detection, grabbing water beakers, and noncontact distance testing has been demonstrated. This work provides a route such as a conformal structure design strategy to enhance the output performance of a microstructure-based TENG sensor.

Liquid crystal elastomers (LCEs) with large deformation under external stimuli have attracted extensive attention in various applications such as soft robotics, 4D printing, and biomedical devices. However, it is still a great challenge to reduce the damage to collimation and enhance the mechanical and actuation properties of LCEs simultaneously. Here, we construct a new method of a double cross-linking network structure to improve the mechanical properties of LCEs. The ureidopyrimidinone (UPy) group with quadruple hydrogen bonds was used as the physical cross-linking unit, and pentaerythritol tetra(3-mercaptopropionate) was used as the chemical cross-link. The LCEs showed a strong mechanical tensile strength of 8.5 MPa and excellent thermally induced deformation (50%). In addition, the introduction of quadruple hydrogen bonds endows self-healing ability to extend the service life of LCEs. This provides a generic strategy for the fabrication of high-strength LCEs, inspiring the development of actuators and artificial muscles.

Adhesive and self-healing elastomers are urgently needed for their convenience and intelligence in biological medicine, flexible electronics, intelligent residential systems, etc. However, their inevitable use in harsh environments results in further enhancement requirements of the structure and performance of adhesive and self-healing elastomers. Herein, a novel self-healing and high-adhesion silicone elastomer was designed by the synergistic effect of multiple dynamic bonds. It revealed excellent stretchability (368%) and self-healing properties at room temperature (98.1%, 5 h) and in a water environment (96.4% for 5 h). Meanwhile, the resultant silicone elastomer exhibited high adhesion to metal and nonmetal and showed stable adhesion in harsh environments, such as under acidic (pH 1) and alkaline (pH 12) environments, salt water, petroleum ether, water, etc. Furthermore, it was applied as a shatter-proof protective layer and a rust-proof coating, proving its significant potential in intelligent residential system applications.