Soft actuators driven by pneumatic or electric means are heavy and clumsy with physical connections, which hinders their applications in human–machine interactive, wearable, and biomedical fields. Herewith, a light fabric bimorph actuator is reported that is driven wirelessly by optical, thermal, and magnetic energy sources. Being fabricated by laminating electrically conductive fabric and biaxially oriented polypropylene film, the actuators show a large bending curvature of 0.75 cm−1 with optical stimulus and 0.55 cm−1 with magnetic stimulus, a response time of 0.27 s with a bending angle of 100° to magnetic stimulus, more than twice faster than previously reported bimorph actuators. Their remarkable performance is attributed to the optimal structural design based on a verified Timoshenko model, electrothermal and optical properties of the conductive fabric coated by copper/nickel. It is greatly enhanced by the large difference of thermal expansion coefficients between the film and fabric. Various wireless controlled prototypes are demonstrated, including a soft gripper, soft kickers, and artificial blooming flowers, illustrating a new way to mass produce cost‐effective bimorph actuators via a simple, green, and fast approach for applications in robots, wearable, and functional textiles.
Piezoelectric catalysis (piezocatalysis) is a physical/chemical process that utilizes piezoelectric potential for accelerating chemical reactions, in which ubiquitous mechanical energies in nature are used for various catalysis applications, e.g., treating organic water pollutants. Despite the high efficiency achieved by piezocatalytic powders, the particles used tend to diffuse in water systems and are hard to be separated, thus causing secondary pollution. Herein, a free‐standing piezocatalytic foam is designed and fabricated, which is composed of BaTiO3 nanoparticles embedded in the PVDF scaffold. The as‐prepared PVDF–BaTiO3 composite foam demonstrates outstanding piezocatalytic efficiency in removing aqueous organics among state‐of‐the‐art integral piezocatalytic platforms, which lie in the synergy of piezoelectric materials and abundant interconnected pores within the foam. Significantly, PVDF–BaTiO3 foam is further applied for purifying natural water samples, by which the permanganate index of the water sample reduces by nearly 30% after 2 h of treatment. In addition, as a monolithic platform, PVDF–BaTiO3 foam is easy to be collected, with high reuse stability and applicability for treating various pollutants, resulting in dominant advantages over powder‐based systems for practical high‐flux wastewater treatment. Herein, a piezocatalytic platform is provided for the effective degradation of organic pollutants in water, with minimal environmental side effects.
Light and flexible thermoelectric generators working around room temperature and within a small temperature range are much desirable for numerous applications of wearable microelectronics, internet of things, and waste heat recovery. Herein, we report a high performance flexible thermoelectric generator made of polymeric thermoelectric composites and heat sink fabrics. The thermoelectric composites comprise n- and p-type Bi2Te3 particles and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, exhibiting a synergic effect that results in Seebeck coefficients higher than those of the constituent alloys and conductive polymer. The flexible and light thermoelectric generator produces an output power of 9.0 mW, a specific output power of 2.3 mW/g, and an areal power density of 6.5 W/m2 at ΔT = 45 K. By using the heat sink fabrics to maintain a large and uniform distribution of temperature difference across the generator, a three-fold increment of the output power is obtained.
This article presents a systematic investigation of the knitted fabrics made from various blends of intrinsically antimicrobial poly (hydroxybutyrate-co-hydroxyvalerate)/polylactide acid filaments and cotton staple fibers. The effects of blend yarn, fabric structures, and distributions of fibers on antimicrobial properties of resultant yarns and knitted fabrics were studied. The relationships among fiber distribution, blend ratio, and anti-microbial properties were experimentally determined for three blend yarns made by sirofil, wrap-spun, and core-spun spinning technologies. The fabrics made from the sirofil-spun and wrap-spun yarns show better anti-microbial effects against Staphylococcus aureus, Klebsiella pneumoniae, and Candida albicans than those of the core-spun yarns, according to the standard AATCC100-2012 Antibacterial Finishes on Textile Materials (American Association of Textile Chemists and Colorists, 2012). An alternative blending method of co-knitting of the pure poly (hydroxybutyrate-co-hydroxyvalerate)/polylactide acid yarns and cotton yarns achieved excellent antimicrobial effects. Furthermore, a wearing trial of underwear made from the blended knitted fabrics was conducted in a nursing home. The wearing comfort of the garments, low-stress mechanical and surface properties of fabrics were evaluated objectively by the Kawabata Evaluation System of Fabric (KESF) system and subjectively by a questionnaire survey to users.
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