Per- and polyfluoroalkyl substances (PFAS) are a class of persistent synthetic compounds, often called “forever chemicals,” that pose a significant threat to public health and the environment. Standard detection methods primarily rely on liquid chromatography and mass spectrometry [1], which is expensive, time-intensive, and requires trained personnel and laboratory infrastructure. While emerging approaches using metal-organic frameworks (MOFs), molecularly imprinted polymers, and lateral flow assays have been explored, they have yet to provide a solution that simultaneously offers part-per-trillion (ppt) sensitivity, high speed detection, and portability [2]–[5]. There is an urgent need for a sensor technology that can provide rapid, on-site, and ultra-sensitive detection to meet regulatory goals, such as the U.S. EPA's 4 ppt health advisory for PFAS [6]. This work addresses this challenge by presenting a novel fluorinated nanowire electrochemical sensor. We leverage a vertically aligned gold “nanograss” morphology to achieve a massive surface-area-to-volume ratio [7]. The wires are then functionalized with perfluoroalkylterminated alkane-thiols (F-thiols) for high PFAS selectivity [8]. We report, for the first time, a sensor based on this platform capable of detecting PFAS at sub-part-pertrillion levels in simulated drinking water. This approach enables ultrafast detection using electrochemical impedance spectroscopy (EIS) and requires only a small sample volume for a viable path toward portable and rapid PFAS monitoring.

To address the need for sustainable high-performance face masks, we demonstrate a strategy that utilizes zein for efficient nanofabrication. An electrospinning process controllably splits the fluid jet, allowing for the creation of face masks composed of fine, fractal-like nanofibers without the need for impurity excipients. This process, enabled by an dipole-force-induced interfacial fluctuation mechanism that we identified, results in face masks that achieve exceptional air filtration performance, surpassing that of commercial N95 masks, while reducing both weight and thickness by half. The significant reduction in material use grants the face masks high optical transparency, facilitating unobstructed facial recognition. Crucially, the pure zein composition allows for the reprocessing of the face masks, contributing to further resource conservation. This work provides a simple, eco-friendly solution for advanced personal protection and points the way toward sustainable wearable devices.

Reusable-rocket powered landing under strong aerodynamics couples variable mass, free final time, and bounded aerodynamic controls through nonlinear velocity-frame dynamics. This paper develops a condensed proportional–integral projected-gradient (PIPG) sequential-convex method whose principal contribution is an exact reduced-space inner architecture. Because the problem contains only six terminal hard equalities and no state path constraints, 217 nodal-state variables and 210 trapezoidal dynamics equalities are eliminated from the 31-node convex subproblem, leaving 101 primal variables and six terminal equalities. Row-orthogonal preconditioning, fixed-size matrix–vector products, and nodewise circular-epigraph projections then yield a customized PIPG kernel. Physical consistency of the angle-dependent axial force is maintained by gradually releasing drag sensitivity between the reference squared angle and an epigraph variable A, together with a convex tightness term. A pointwise Hamiltonian argument shows that the fully released limiting subproblem admits a tight optimum satisfying A=α^2+β^2. Deterministic annealing, two-stage inner accuracy, and a rejected-on-failure threefold extrapolation are secondary outer-loop accelerators.

Predictive modelling of triboelectric nanogenerators (TENGs) remains fragmented across analytical theories, finite-geometry solvers and disconnected simulation workflows. These disparate approaches must be unified into an executable framework to advance quantitative TENG research.Here we introduce a charge-defined modelling framework and implement it as TENG-CLAW, a physics-governed platform for traceable TENG simulation. The framework establishes a self-consistent electrostatic hierarchy in which triboelectric charges, pre-charging charges and compensating electrode charges serve as defining state variables.This hierarchy connects the infinite plate analytical limit for near-uniform fields with finite-geometry numerical formulations required for edge-dominated devices. Built on this basis, TENG-CLAW converts user-defined research requests into physically admissible simulation tasks, so that generated outputs are tied to explicit charge states, boundary conditions, solver routes and reusable artifacts across spatial, temporal, field-level, comparative and reporting workflows. This work establishes a rigorous computational basis for interpreting TENG mechanisms and provides reproducible research infrastructure for simulation and physics-guided device design.

Metal halide perovskite solar cells (PSCs) have emerged as a promising candidate for next-generation photovoltaic technologies. Nevertheless, the inherent heterogeneity in polycrystalline perovskite films fabricated using the classic one-step anti-solvent method remains a significant challenge. Specifically, this "top-down" crystallization process results in non-uniform nucleation and a stress gradient across the film, which hinder charge transport and compromise device stability. To address this issue, we pre-deposited a 2D perovskite crystal to mediate the template growth of the 3D perovskite film. And various in-situ characterizations have reflected this evolution process of template growth. This strategy suppressing the random nucleation process induced by the heterointerface and facilitating the formation of high-quality perovskite films, which achieved nearly uniform stress distribution throughout the entire film (top-bottom difference <5 MPa) and suppresses the non-radiative recombination induced by inhomogeneity stress. As a result, Cs-0.05(FA(0.95)MA(0.05))(0.95)Pb(I0.95Br0.05)(3) and Cs(0.05)MA(0.1)FA(0.85)PbI(3)-based devices achieve efficiencies of 25.31% and 26.46%, respectively. Furthermore, the devices achieved a relative improvement in operational stability under maximum power point tracking.

This work presents multimodal normal and shear force tactile sensing via piezoelectric micromachined ultrasonic transducers (PMUTs). The key advances are: (1) the first PMUT-based multimodal tactile sensor for contact-rich robotic manipulations; (2) normal force sensing with a resolution of 0.1 N via the time-of-flight (ToF) scheme; and (3) decoupled multi-axis normal/shear force sensing via a profile scanning design and elastomer thinning effects. The ability to decouple forces for tactile sensing is critical for applications in sophisticated robotic manipulation systems.

Robotic pick-and-place is fundamental to automated handling of fragile, irregularly shaped, and hard-to-access objects. Liquid metal grippers enable conformal grasping via wetting and reversible phase transitions, but gallium-based alloys suffer from supercooling and high surface tension that hinder automated use as end-effectors. Here, we report a magnetic liquid-wetting gripper based on a gallium-tin alloy embedded with iron particles for pick-and-place of objects with diverse shapes. Iron particles serve as heterogeneous nucleation sites to mitigate supercooling, while active magnetic vibration helps the alloy overcome high surface tension, enabling wetting and adhesion. Coupling magnetic-vibration-assisted wetting with Peltier cooling and heating allows reversible liquid-solid switching for fixation during transfer and on-demand release. The gripper achieves repeatable pickup, transfer, and release of smooth, rugged, ultrathin, and needle-like objects, with a lifting capacity up to 10 kg.

We report a dual-action energy harvester featuring a synergistic copolymeric network designed for efficient atmospheric water harvesting (AWH) and moisture-induced electricity generation. The scientific significance of this work lies in the first-time application of a zwitterionic [2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (DMAPS) and acrylamide (AM) copolymer for AWH. The water-harvesting film is composed of DMAPS and AM, which is dried, soaked in LiCl solution, frozen using liquid nitrogen, and freeze-dried for 24 h to obtain P(DMAPS-co-AM)-LiCl with porous monolithic structure. The energy-harvesting layer is assembled from a P(DMAPS-co-acrylic acid (AA)) copolymer. By incorporating the DMAPS monomer into both layers, we establish a chemically compatible and homologous interface that facilitates efficient ionic transport and minimizes interfacial resistance-a critical advantage for dual-action devices often overlooked in previous studies. Dynamic vapor adsorption measurements demonstrate superior hygroscopicity, with an equilibrium water capacity of 0.873 g/g at 30% RH, which increases to 1.72 g/g at 60% RH. Electrical generation is proposed to arise primarily from the dissociation and directional migration of protons (H+) across the zwitterionic interface, a mechanism supported by cyclic voltammetry analysis. Under an arid condition of 30% RH, the system produces a stable open-circuit voltage of 0.65 V and an average short-circuit current density of 1.15 μA/cm2 for over 2500 min continuously, achieving an energy density of ∼112.1 mJ/cm2 and a maximum power density of 23.4 nW/cm2. As such, this integrated material approach offers a robust and scalable route for autonomous, self-powered systems in low-humidity environments.

Soft Li-ion batteries, based on conventional organic electrolytes, face performance degradation challenges due to moisture penetration and safety concerns due to possible leakage of toxic fluorine compounds and flammable solvents under mechanical damage. We design a water-scarce hydrogel electrolyte with fluorine-free lithium salt to achieve wide electrochemical stability window (up to 3.11 volts) in ambient air without hermetic packaging while balancing high stretchability (1348%), ion conductivity (41 millisiemens per centimeter), and self-healing capabilities for mechanically and chemically safe stretchable Li-ion batteries. Molecular synergy between hydrophilicity and lithiophilicity of zwitterionic polymer backbone is revealed by molecular dynamics simulations. The battery exhibits capacity retention under harsh mechanical stresses—enduring stretching, twisting, folding, and multiple through-punctures by a needle—while self-healing from repeated through cuts by a razor blade. Stable ambient operation for 1 month over 500 charge-discharge cycles (average coulomb efficiency, 95%) is achieved. A prototype self-healing electronic system with embedded soft batteries demonstrates practical application as a durable embodied energy source.

This work introduces the continuous volumetric measurement of temperature, humidity, and pressure using ultrasonic signals for the first time via PMUTs (piezoelectric micromachined ultrasonic transducers). Key advancements over existing methods include: (1) concurrent monitoring of temperature, relative humidity, and atmospheric pressure over 5 days by using ultrasonic signals; (2) volumetric measurements over a 5-meter distance in contrast to traditional localized point measurements; and (3) the integration of machine learning for enhanced accuracy with RMSE errors of 0.13 degrees C, 1.65% RH. and 0.85 hPa as validated by commercial thermometer, hygrometer, and barometer, respectively. This innovative ultrasound-based approach provides a cost-effective, energy-efficient solution for precise environmental control in future buildings.

This work proposes a dynamic package scheme for piezoelectric micromachined ultrasonic transducers (PMUTs) by a Shape Memory Alloy (SMA) controlled platform to actively change the acoustic wave directivity patterns and frequency responses. Innovations include: (1) a shape-morphing package capable of switching between two states in seconds using SMA Nitinol wires; (2) a 278% increase in the received signal at 50 kHz between two states at an 45 degrees angle; and (3) a design scheme by generative and surrogate machine learning models for optimal parameters according to desired outputs. The dynamic package enables designated acoustic fields across different frequencies for potential applications in ultrasonic communication, medical imaging, and environmental sensing.

Interactive surfaces have garnered significant attention in Human-Computer Interaction, with fluid-driven actuators being a promising actuation technology due to their flexible form factors and multimodal interactivities. However, traditional fluid-driven systems typically rely on bulky and noisy electromechanical hardware, limiting their portability and practicality. While recent work has introduced compact hydraulic actuators like electroosmotic pumps (EOPs) in haptic devices, their potential for building multifunctional interactive surfaces remains largely unexplored. In this work, we present MorphingSkin, a skin-like platform that integrates multiple, multimodal hydraulic actuators using flexible EOPs as lightweight and self-contained fluidic actuators. We introduce the architecture of MorphingSkin and its versatile design space for multimodal actuation in force, shape, optical, and weight domains. We demonstrate interactive and robotic applications that integrate multiple actuators working collectively within a single MorphingSkin device. Through this work, we envision the future of using MorphingSkin technology for interactive surfaces that integrate flexible form factors and multimodal actuation capabilities.

This work introduces contactless ultrasonic fluid viscosity and density monitoring using piezoelectric micromachined ultrasonic transducers (pMUTs) for the first time. Key advancements include: (1) non-contact and simultaneous liquid viscosity and density measurements; (2) 98% classification accuracy for four tested liquids; and (3) a mean absolute error (MAE) of 0.79 cp for a viscosity range from 0.98 cp to 39.44 cp, and a MAE of 12.6 kg center dot m(-3) for a density range from 997.8 to 1035.3 kg center dot m(-3). By removing the requirement for the direct contract of MEMS sensors to the testing fluid, this approach allows broader liquid measurements, including corrosive or hard-to-clean fluids, without complex experimental setups.

This work presents an alignment-free blood vessel monitoring microsystem based on a piezoelectric micromachined ultrasonic transducer (pMUT) array using a beam steering scheme. Compared with the literature, three key achievements include: (1) quantifications for the impact of misalignments during the ultrasound detection of a brachial artery; (2) a beam steering strategy without manual alignment to expand the field of view; (3) a new technique based on the fast Fourier transform (FFT) phase shift to measure relative location changes of the anterior and posterior artery wall. Validations on the brachial artery of a volunteer show the successful extraction of the artery diameter with detailed dynamic features. As such, this work advances the field of non-invasive cardiovascular monitoring using pMUT.

Point-of-care sensors are pivotal for early disease diagnosis, significantly advancing global health. Surface plasmons, the collective oscillations of free electrons under electromagnetic excitation, have been widely studied for biosensing due to their electromagnetic field enhancements at sub-wavelength scales. We introduce a plasmonic biosensor on a compact photonic integrated circuit (PIC) enhanced by exceptional points (EPs). EPs, singularities in non-Hermitian optical systems, provide extreme sensitivity to external perturbations. They emerge when two or more complex resonating modes merge into a single degenerate mode. We demonstrate an EP in a single coupled nanoantenna particle positioned in a uniquely designed silicon nitride slot-waveguide, which we call a junction-waveguide. By laterally shifting two optically coupled gold nanobars of different lengths, we achieve a single particle EP. The junction-waveguide enables efficient coupling of the plasmonic nanoantenna to the waveguide mode. The system integrates a four-port Mach–Zehnder interferometer (MZI), allowing for simultaneous measurements of the amplitude and phase of EP, facilitating highly accurate real-time eigenvalue extraction. For biosensing, we encapsulated the detection zone with a microchannel, enabling low-volume and simple sample handling. Our single particle integrated EP sensor demonstrates superior sensitivity compared to the corresponding linear diabolic point (DP) system under both local and bulk sensing schemes, even at large perturbations. Our studies revealed that the integrated EP sensor can detect a single molecule captured by the nanobars with the average size ranging from 10 to 100 nm. The proposed EP biosensor, with its extreme sensitivity, compact form, and real-time phase sensing capabilities, provides an approach for detecting and quantifying various biomarkers such as proteins and nucleic acids, offering a unique platform for early disease diagnosis.

This work presents a gas sensor based on a field-effect transistor (FET) made of semiconducting single-walled carbon nanotubes gated by ionic liquids. Ionic liquids are used as: 1) gating electrolytes for the transistor on/off operation to enhance gas sensing sensitivity, and 2) functionalization to increase sensing selectivity. Prototype transistors have achieved high on/off ratios (10(6)similar to 10(7)) with low operation voltages (threshold voltage similar to 0.3 V at source drain voltage of 50 mV). The sensitivity of NH3 gas is enhanced by over 4 times through cation and anion variation in ionic liquids, while responses to different gases (NH3 and CH4) are observed by distinct patterns. By tuning the operation regime of the transistor through the gate bias voltage, a 5-fold increase in sensitivity is demonstrated for real-time room temperature detection of 100 ppm methane in nitrogen gas. As such, this new gas sensing method could open up new avenues for miniaturized electronic noses with high sensitivity and selectivity.

Microfabrication technologies have been utilized for the construction of functional microstructures with large volume and low cost, which have led to investigations on the design, packaging, and integration of piezoelectric and piezoelectret materials for various applications in sensors, actuators, and microsystems. For piezoelectric materials, we have been working on piezoelectric micromachined ultrasonic transducers (PMUTs) based on AlN, Lithium Niobate, and KNN((K,Na)NbO) films. For piezoelectret materials, we have made wearable actuators and sensors to generate force as high as 20 mN and to detect ultralight matters such as dandelion seed, respectively. An ultra-robust and fast moving piezoelectric robot like those of cockroaches will also be discussed.

This work reports a biodegradable and self-healable piezoelectric hydrogel for the first time which is suitable for biocompatible solid-state transducer applications. Three key advancements are achieved as compared to the state-of-the-art works: (1) biocompatible hydrogels with both self-healing and biodegradation capabilities to endure short-term mechanical damage and accomplish long-term self-dissemination; (2) a measured piezoelectric constant of 35 pC/N, which is 1.4 times higher than that of biocompatible PVDF; and (3) device demonstrations of a heart rate sensor and an energy harvester. As such, this work opens a new class of piezoelectric materials for biocompatible transducers.

This paper presents subcutaneous and continuous blood pressure (BP) monitoring using aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducers (PMUTs) in an ambulatory sheep. A 37 × 45 PMUTs array with a footprint of 5 × 5 mm2 has been designed and fabricated as a prototype device. The deep reactive ion etching (DRIE) process to open the backside holes on the silicon substrate has been optimized to create active device diaphragms with a radius of 29 μm. The resulting PMUT unit has a measured resonant frequency of 6.5 MHz in water, an output acoustic pressure of 28 kPa at a distance of 10 mm, and a 6-dB bandwidth of about 33 ± 2.1 and −2.9 ± 1.4 mmHg, respectively, which meets the clinical standard as calibrated by a gold-standard arterial line pressure sensor. As such, this system highlights the potential applications in silent, continuous, and highly accurate BP monitoring for hypertension patients using this implantable MEMS-based technology.