Sponge-like porous polyvinyl alcohol/chitosan-based hydrogel with integrated cushioning, pH-indicating and antibacterial functions.

Developing a packaging material with integrated cushioning, intelligent and active functions is highly desired but remains challenging in the food industry. Here we show that a sponge-like porous hydrogel with pH-indicating and antibacterial additives can meet this requirement. We use polyvinyl alcohol and chitosan as the primary polymers to construct a hydrogel with hierarchical structures through a freeze-casting method in combination with salting-out treatment.

Sensitive, Robust, Wide-Range, and High-Consistency Capacitive Tactile Sensors with Ordered Porous Dielectric Microstructures.

Flexible capacitive tactile sensors show great promise in personalized healthcare monitoring and human-machine interfaces, but their practical application is normally hindered because they rarely possess the required comprehensive performance, that is, high pressure sensitivity and fast response within a broad pressure range, high structure robustness, performance consistency, etc. This paper aims to engineer flexible capacitive pressure sensors with highly ordered porous dielectric microstructures and a 3D-printing-based fully solution-processable fabrication process. The proposed dielectric layer with uniformly distributed interior microporous can not only increase its compressibility and dynamic response within an extended pressure range but also enlarge its contact area with electrodes, contributing to a simultaneous improvement in the sensitivity, response speed, detection range, and structure robustness.

Topoarchitected polymer networks expand the space of material properties.

Many living tissues achieve functions through architected constituents with strong adhesion. An Achilles tendon, for example, transmits force, elastically and repeatedly, from a muscle to a bone through staggered alignment of stiff collagen fibrils in a soft proteoglycan matrix. The collagen fibrils align orderly and adhere to the proteoglycan strongly.

Toughening Mechanism of Unidirectional Stretchable Composite.

Composite materials have been long developed to improve the mechanical properties such as strength and toughness. Most composites are non-stretchable which hinders the applications in soft robotics. Recent papers have reported a new design of unidirectional soft composite with superior stretchability and toughness.

Stretchable materials of high toughness and low hysteresis.

In materials of all types, hysteresis and toughness are usually correlated. For example, a highly stretchable elastomer or hydrogel of a single polymer network has low hysteresis and low toughness. The single network is commonly toughened by introducing sacrificial bonds, but breaking and possibly reforming the sacrificial bonds causes pronounced hysteresis.

Influences of supra-physiological temperatures on microstructure and mechanical properties of skin tissue.

Thermal therapies under supra-physiological temperatures are increasingly used to treat skin diseases (e.g., superficial melanoma, removal of port-wine stains pigmented and cutaneous lesions).