Shuhuai Yao

Vision‐based tactile sensors are promising for robotic perception but suffer from poor durability and limited sensitivity to fine textures and slip. To overcome these limitations, we propose a bioinspired hard‐soft hybrid tactile skin that combines rigid polydimethylsiloxane (PDMS)/SiO ₂ microcolumns with a compliant PDMS film to simultaneously improve durability and tactile perception. The rigid microcolumns serve as a wear‐resistant contact interface while enhancing surface‐induced tactile vibrations, whereas the compliant film ensures efficient transmission of contact forces. Material wear tests show the composite achieves a 76.5% reduction in wear depth, with post‐wear roughness only 3.8% of pure PDMS. The sensor maintains stable sensing performance after 210,000 loading cycles, with only 4.0% signal drift during the final 10,000 cycles, representing more than an order‐of‐magnitude improvement in lifetime compared with previously reported vision‐based tactile sensors. Furthermore, the microcolumn‐structured sensor enables high‐sensitivity slip detection by exploiting a transient peak at slip initiation and facilitates accurate recognition of texture periodicity and orientation via frequency‐domain analysis. This work presents a bioinspired hard‐soft hybrid design strategy for developing durable vision‐based tactile sensors with physically interpretable multimodal perception for long‐term robotic interaction.

At low pressures, water often experiences chaotic multiphase transitions that complicate fluid management. Here, we demonstrate that a minimal addition of glycerol to a water droplet can transform these disruptive behaviors into highly regulated dynamics. Instead of typical breakup or rapid self‐propulsion, freezing glycerol‐water droplets enter a state of gentle, cyclic levitation, repeatedly undergoing “dwelling, liftoff, flight, and impact.” We reveal that this phenomenon arises from the dual roles of glycerol. Freeze‐concentration preserves interconnected liquid regions and prevents the formation of a closed outer ice shell, thereby limiting the accumulation of expansion‐induced stress. In parallel, glycerol lowers the equilibrium freezing temperature, reducing the asymmetric vaporization recoil that drives self‐propulsion during recalescence. The suppression of these instabilities enables a cyclic droplet motion driven by self‐sustaining thermal oscillation, where basal heating enhances overpressure for liftoff and in‐flight vaporization cooling resets the cycle. Our findings unveil a distinct regime of vaporization‐driven droplet dynamics that is tunable through composition, offering new strategies for fluid management under extreme conditions, with implications ranging from thermal management to space exploration.

Elastocaloric cooling is emerging as a viable solid-state competitor to standard vapor-compression systems. By utilizing the latent heat from stress-induced phase changes in shape memory alloys (SMAs), elastocaloric cooling enables thermal management with zero direct greenhouse gas emissions. This review surveys the current state of elastocaloric cooling technology, identifies the key hurdles to commercialization, and discusses engineering strategies ranging from microstructural design and manufacturing scale-up to system integration aimed at practical implementation. We structure the analysis around four key areas: (1) system fundamentals, including materials, actuation, and heat transfer; (2) material limitations, specifically the trade-off between adiabatic temperature change, fatigue life, cooling capacity and operating temperature windows; (3) the evolution of prototypes, ranging from simple conductive setups to advanced regenerative designs; and (4) the roadmap for scaling these systems up. While recent work in microstructural and compositional engineering is encouraging, a persistent challenge remains: efforts to increase the adiabatic temperature change often compromise fatigue life, while broadening the operating temperature range generally lowers peak cooling performance. Moving forward, the focus must shift to aligning material science with advanced manufacturing to address these multi-physics challenges. Elastocaloric cooling research is moving from fundamental studies toward device‐level and application‐oriented development. In the near term, it appears most promising for compact niche uses such as portable cooling, while residential and automotive applications remain longer‐term prospects pending further advances in materials and system design.

NiTi-based elastocaloric cooling presents an environmentally friendly solid-state alternative to vapor-compression refrigeration. However, conventional NiTi refrigerant fabrication relies on thermomechanically intensive processes that limit geometric versatility while increasing production time, costs, and material waste. Although 3D printing offers a potential solution, existing 3D-printed NiTi alloys face a critical trade-off between cyclic durability and specific temperature change (the adiabatic temperature change per unit driving stress). Here, we address these challenges by developing a high-performance 3D-printed NiTi alloy with defect-minimized, bimodal microstructures. This design facilitates stress-induced martensitic phase transformation while suppressing dislocation slip and crack propagation. Consequently, the alloys can withstand a record-high 3 million cycles without failure, while simultaneously achieving an 11-fold enhancement in specific temperature change over state-of-the-art 3D-printed counterparts (increasing from 2.97 to 33.6 °C·GPa⁻¹). Furthermore, we realize direct 3D printing and integration of NiTi refrigerants into a macroscale cooling prototype, which achieves a temperature span of 20 °C. Our work establishes 3D-printed NiTi alloys as viable elastocaloric refrigerants, unlocking a 3D-printing-enabled pathway toward sustainable cooling systems.

Regulating solar heat gain is crucial for reducing heating, ventilation, and air conditioning (HVAC) energy consumption in buildings and promoting sustainable responses to climate change. Current thermochromic materials suffer from poor durability and limited optical modulation. Here, the study presents a durable thermochromic coating based on an organogel-higher alkane (HA) composite. The reversible phase change of HA within the organogel induces light reflection, scattering, and diffraction, while carbon black particles enhance the absorptance modulation, achieving a maximum change of 0.35. For practical application on cement, where a highly reflective layer is applied beneath, the absorptance modulation can reach 0.25, exceeding reported values for other thermochromic systems that could be applied to the roof or wall. The material withstands prolonged UV exposure and repeated thermal cycling without degradation, making it suitable for real-world applications. Simulations incorporating a reflective underlayer demonstrate potential annual HVAC energy savings of up to 3% across diverse climate zones. This work introduces a robust, scalable, and season-adaptive thermochromic coating for sustainable building energy management.

Elastocaloric cooling using shape-memory alloys (SMAs) is a promising greenhouse gas (GHG)-free alternative to conventional vapour-compression refrigeration that relies on high global warming potential (GWP) gas refrigerants^1,2,3,4. However, existing elastocaloric systems have not yet reached sub-zero Celsius temperatures, which restricts their application in various freezing scenarios^5,6. Here we constructed a compression-based, regenerative elastocaloric cooling device using low-transition-temperature tubular NiTi units in a cascaded configuration. The selected NiTi alloy exhibited superelasticity and substantial entropy changes down to −20 °C. Moreover, low-freezing-point aqueous calcium chloride solution was used as the heat-transfer fluid, ensuring effective flow at low operational temperatures. Our desktop device achieved a heat-source temperature of −12 °C from a room-temperature heat sink, paving the way for next-generation green elastocaloric freezing technologies.