In situ, time-resolved characterisation of an alginate–acrylamide tough hydrogel dynamic formation process indicate routes to intervention and modification of chemo-physico-mechanical properties.

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The present research makes use of a braiding-cum-weaving technique for the fabrication and investigation of electricity-induced heating fabrics. Braided conductive yarns (BCYs) were produced using a Maypole braiding machine by introducing conductive copper filament as the core and polyester multifilament yarn as the sheath. A different number of polyester yarns, 6-, 10-and 16-end, were used to cover the copper core. Electrically heating fabrics (e-HFs) were fabricated by interweaving the BCYs through pick insertion in a plain-woven construction at 4-, 8-and 12-pick spacing. Various electro-mechanical tests were carried out on the BCYs and e-HFs. The mechanical performance of 16-end BCY was the most superior while 6-end BCY exhibited the poorest performance amongst the three BCY-types. The temperature profiles obtained via thermal mapping elucidate the difference in the heat-barrier effect of each of the BCYs. It also shows the presence of overlapping concentric (cylindrical) isotherms running along the axes of the BCYs. These isotherms have shown to significantly affect the temperature uniformity on the e-HF surface. Heating response under different variables-pick-spacing, time, voltage and input power, were evaluated, and direct correlations were found. A temperature of about 89.8 °C was attained at 5 V after 40 min of heating. For an input power of 3, 5 and 7 W, a maximum temperature of 40.5, 48.8 and 55.3 °C was measured for different e-HFs. Wash and sweat durability tests were also carried out to corroborate the utility of the e-HFs for day-today usage. These tests proved to have a minimal detrimental effect on the heating performance of the e-HFs establishing a good utilitarian quotient of such material for the purpose of wearable electronics and essentially, as active heating garments.

Functionally gradient materials (FGM) have gradual variations in their properties along one or more dimensions due to local compositional or structural distinctions by design. Traditionally, hard materials (e.g., metals, ceramics) have been used to design and fabricate FGMs; however, there has been increasing interest in polymer‐based soft and compliant FGMs mainly because of their potential application in the human environment. Soft FGMs are not only ideally suitable to manage interfacial problems in dissimilar materials used in many emerging devices and systems for human interaction, such as soft robotics and electronic textiles and beyond. Soft systems are ubiquitous in our everyday lives; they are resilient and can easily deform, absorb energy and adapt to changing environments. Here, we discuss the basic design and functional principles of biological FGMs and their manmade counterparts using representative examples. The remarkable multifunctional properties of natural FGMs resulting from their sophisticated hierarchical structures, built from a relatively limited choice of materials, offer a rich source of new design paradigms and manufacturing strategies for manmade materials and systems for emerging technological needs. Finally, we highlight the challenges and potential pathways to leverage soft materials' facile processability and unique properties to wards functional FGMs.This article is protected by copyright. All rights reserved