Electrically conductive elastomer composites (CECs) with segregated networks of conductive nanofillers show high potential in stretchable strain sensors due to balanced mechanical and electrical properties, yet the sensitivity at low strain is generally insufficient for practical application. Herein, we report an easy and effective way to improve the resistive response to low strain for CECs with segregated network structure via adding stiff alumina into carbon nanostructures (CNS). The CEC containing 0.7 ​wt% CNS and 5 ​wt% Al₂O₃ almost sustains the same elasticity (elongation at break of ~900%) and conductivity (0.8 ​S/m) as the control, while the piezoresistive sensitivity is significantly improved. Thermoplastic polyurethane (TPU) composites with a segregated network of hybrid nanofillers (CNS and Al₂O₃) show much higher strain sensitivity (Gauge factor, GF ​= ​566) at low strain (45% strain) due to a local stress concentration effect, this sensitivity is superior to that of TPU/CNS composites (GF ​= ​11). Such a local stress concentration effect depends on alumina content and its distribution at the TPU particle interface. In addition, CECs with hybrid fillers show better reproducibility in cyclic piezoresistive behavior testing than the control. This work offers an easy method for fabricating CECs with a segregated filler network offering stretchable strain sensors with a high strain sensitivity.

As a renewable and environment-friendly technology for seawater desalination and wastewater purification, solar energy triggered steam generation is attractive to address the long-standing global water scarcity issues. However, practical utilization of solar energy for steam generation is severely restricted by the complex synthesis, low energy conversion efficiency, insufficient solar spectrum absorption and water extraction capability of state-of-the-art technologies. Here, for the first time, we report a facile strategy to realize hydrogen bond induced self-assembly of a polydopamine (PDA)@MXene microsphere photothermal layer for synergistically achieving wide-spectrum and highly efficient solar absorption capability (~ 96% in a wide solar spectrum range of 250-1,500 nm wavelength). Moreover, such a system renders fast water transport and vapor escaping due to the intrinsically hydrophilic nature of both MXene and PDA, as well as the interspacing between core-shell microspheres. The solar-to-vapor conversion efficiencies under the solar illumination of 1 sun and 4 sun are as high as 85.2% and 93.6%, respectively. Besides, the PDA@MXene photothermal layer renders the system durable mechanical properties, allowing producing clean water from seawater with the salt rejection rate beyond 99%. Furthermore, stable light absorption performance can be achieved and well maintained due to the formation of ternary TiO₂/C/MXene complex caused by oxidative degradation of MXene. Therefore, this work proposes an attractive MXene-assisted strategy for fabricating high performance photothermal composites for advanced solar-driven seawater desalination applications.

Recently, graphene foam (GF) with a three-dimensional (3D) interconnected network produced by template-directed chemical vapor deposition (CVD) has been used to prepare composite phase-change materials (PCMs) with enhanced thermal conductivity. However, the pore size of GF is as large as hundreds of micrometers, resulting in a remarkable thermal resistance for heat transfer from the PCM inside the large pores to the GF strut walls. In this study, a novel 3D hierarchical GF (HGF) is obtained by filling the pores of GF with hollow graphene networks. The HGF is then used to prepare a paraffin wax (PW)-based composite PCM. The thermal conductivity of the PW/HGF composite PCM is 87% and 744% higher than that of the PW/GF composite PCM and pure PW, respectively. The PW/HGF composite PCM also exhibits better shape stability than the PW/GF composite PCM, negligible change in the phase-change temperature, a high thermal energy storage density that is 95% of pure PW, good thermal reliability, and chemical stability with cycling for 100 times. More importantly, PW/HGF composite PCM allows light-driven thermal energy storage with a high light-to-thermal energy conversion and storage efficiency, indicating its great potential for applications in solar-energy utilization and storage.