Visualizing thermal distribution through hydrogel confined ionic system.

Effective thermal regulation has shown great impacts on tremendous aspects of our life and manufacture. However, the invisible nature of thermal field brings us inconvenience or even security hazard. Herein, we present a method to visualize thermal distribution with the aid of a thermally active material. An ionic liquid with lower critical solution temperature is mixed within hydrogel to demonstrate a hydrogel confined ionic system (HCIS). This particular system turns turbid as the temperature exceeds an established temperature threshold, which is adjustable through applying different concentrations of HCl or NaCl. The system offers straightforward images of the spatial thermal distribution whether simple or sophisticated, which is fully in line with computational simulation. The system is further demonstrated with great promise for the application in fire warning to lower the threat induced by electrical failure. The HCIS opens a practical avenue to visualize thermal distribution and improve our thermal regulation efficiency.

Interfacial Diffusion Printing: An Efficient Manufacturing Technique for Artificial Tubular Grafts.

Despite great progresses in bioprinting materials and technologies, immense challenges still remain when printing tubular tissues or organs with satisfying mechanical and chemical properties, such as blood vessel, colon, and trachea. Herein, a promising extrusion system based on an interfacial diffusion printing (IDP) technique for one-step printing of tubular tissue grafts is proposed. Specifically, this technique offers great convenience to prepare hollow hydrogel fibers with excellent mechanical properties and satisfactory biocompatibility. The tubular diameter can be readily adjusted within 6 mm, which renders the possibility of these hydrogel tubes to serve as small-diameter vascular grafts. In the model of animal trials, the hydrogel grafts with the capability of enduring arterial pressure are mechanically stable in rabbit carotid artery replacement. Because of its intrinsic simplicity and generality, the IDP technique is considered to be one of the reliable choices for more complicated bioengineering.

Inherently magnetic hydrogel for data storage based on the magneto-optical Kerr effect.

In this data explosion age, a large amount of data is generated every day. Such a fast data growth has aroused great interest in the field of data storage. Conventional data storage materials are mainly composed of hard and brittle materials but they may break in the case of mechanical operations, causing irreversible data loss. In this work, efforts have been devoted to fabricating a flexible and stretchable double network hydrogel for data storage based on the magneto-optical Kerr effect. The hydrogel possesses a storage modulus of over 104 Pa and remains unbroken under a strain of 3000%. The surface of the hydrogel is patterned with diamagnetic parts and paramagnetic parts alternately. When placed under a magnetic field, the surface of the hydrogel reflects the incident laser beam and changes the polarization plane of the reflected light. The outstanding flexibility and inherent magnetic properties of this hydrogel lay the groundwork for data storage and guarantee data safety.

A Polypyrrole Elastomer Based on Confined Polymerization in a Host Polymer Network for Highly Stretchable Temperature and Strain Sensors.

For the purpose of stretchable electronics, broad interests have been paid to elastic conductors by which high tensile strain over 100% can be readily achieved. Here, a scalable-processing, dyeing-like strategy for highly stretchable polypyrrole elastomer (1450% in strain) is conceived without particular topological design. This approach effectively improves the mechanical properties of the classic insoluble polypyrrole by confined polymerization within an elastic polymer network. In terms of the easy processing, it is technically possible to prepare stretchable electronics with arbitrary shape and size for wearable electronics with low cost. The mechanism of interpenetrated networks coexisting with microphase separation is comprehensively illustrated at molecular scale. The as-fabricated polypyrrole elastomers are utilized as temperature or strain sensors for automatic fishing and region-distinct dual signal sensing. Further integration of multiple sensors offers immediate alarm for old people falling at home, which thereby proves its promising potential in practical applications.

Light-Triggered CO2 Breathing Foam via Nonsurfactant High Internal Phase Emulsion.

Solid materials for CO2 capture and storage have attracted enormous attention for gaseous separation, environmental protection, and climate governance. However, their preparation and recovery meet the problems of high energy and financial cost. Herein, a controllable CO2 capture and storage process is accomplished in an emulsion-templated polymer foam, in which CO2 is breathed-in under dark and breathed-out under light illumination. Such a process is likely to become a relay of natural CO2 capture by plants that on the contrary breathe out CO2 at night. Recyclable CO2 capture at room temperature and release under light irradiation guarantee its convenient and cost-effective regeneration in industry. Furthermore, CO2 mixed with CH4 is successfully separated through this reversible breathing in and out system, which offers great promise for CO2 enrichment and practical methane purification.

Biomimetic Bone-like Hydroxyapatite by Mineralization on Supramolecular Porous Fiber Networks.

Hydroxyapatite (HA), the main inorganic component of bone tissue, is mineralized with collagen fibril scaffolds during bone formation. Inspired by the process, a self-assembled porous network architecture was designed and synthesized by using the 2-ureido-4[1H]-pyrimidone (UPy) modified glycerol molecule UPy-Gly, which was further utilized as a template for biomimetic mineralization. When incubated in simulated body fluid (SBF), the HA nucleus first formed in the holes of the template by the induction of hydroxyls on the surface, grew along the nanofibers, and fused with the template to fabricate hydroxyapatite composites (UPy-Gly/HA). Transmission electron microscopic observation demonstrates that the mineral clusters are accumulated by lamella-like nano hydroxyapatite and the elasticity modulus measured by atomic force microscopy is about 5.5 GPa, which is quite close to the natural cancellous bone tissue of human both in structure and in mechanical properties. The Cell Counting Kit 8 (CCK-8) assay of UPy-Gly and UPy-Gly/HA shows noncytotoxicity to mouse fibroblast L-929 cells. This bioinspired composite will be a promising material for potential use in bone tissue implantation and regeneration engineering.