E-textile consisting of natural fabrics has become a promising material to construct wearable sensors due to its comfortability and breathability on the human body. However, the reported fabric-based e-textile materials, such as graphene-treated cotton, silk, and flax, generally suffer from the electrical and mechanical instability in long-term wearing. In particular, fabrics on the human body have to endure heat variation, moisture evaporation from metabolic activities, and even the immersion with body sweat. To face the above challenges, here we report a wool-knitted fabric sensor treated with graphene oxide (GO) dyeing followed by l-ascorbic acid (l-AA) reduction (rGO). This rGO-based strain sensor is highly stretchable, washable, and durable with rapid sensing response. It exhibits excellent linearity with more than 20% elongation and, most importantly, withstand moisture from 30 to 90% (or even immersed with water) and still maintains good electrical and mechanical properties. We further demonstrate that, by integrating this proposed material with the near-field communication (NFC) system, a batteryless, wireless wearable body movement sensor can be constructed. This material can find wide use in smart garment applications.

Scarcity of stiff, yet compliant, materials is a major obstacle toward biological‐like mechanical systems that perform precise manipulations while being resilient under excessive load. A macroscopic cellular structure comprising two pre‐stressed elastic “phases” is introduced, which displays a load‐sensitive stiffness that drops by 30 times upon a “pseudoductile transformation” and accommodates a fully recoverable compression of over 60%. This provides an exceptional 20 times more deformability beyond the linear‐elastic regime, doubling the capability of previously reported super‐elastic materials. In virtue of the pre‐stressing process based on thermal‐shrinkage, it simultaneously enables a heat‐activated self‐formation that transforms a flat laminate into the metamaterial with 50 times volumetric growth. The metamaterial is thereby inherently lightweight with a bulk density in the order of 0.01 g cm−3, which is one order of magnitude lower than existing super‐elastic materials. Besides the highly programmable geometrical and mechanical characteristics, this paper is the first to present a method that generates single‐crystal or poly‐crystal‐like 3D lattices with anisotropic or isotropic super‐elasticity. This pre‐stress‐induced adaptive stiffness with high deformability could be a step toward in situ deployed ultra‐lightweight mechanical systems with a diverse range of applications that benefit from being stiff and compliant.

Digital light processing to realise patterned and gradient bilayered composites that self-fold in response to near infra-red triggers.

Current gossamer space structures such as solar sails usually rely on bracing structures, inflation gas, or centrifugal force to deploy and maintain a structural shape, which leads to a system that is sometimes complicated, while a concise system can be achieved if the gossamer structure could self-rigidise and support load. The present study proposes a self-folding polymer membrane based on space-qualified materials and is potentially mass-producible by industrial rollto-roll processes. It can permanently transform a flat gossamer membrane into a load-bearing 3D configuration when heated by sunlight in space, while the foldinginduced shape bifurcation and buckling are prevented using a kirigami hinge design. The shape transformation is demonstrated in lab by a tubular and an origami structure that are formed from a flat membrane when heated to 82 C in oven. Thermal radiation analyses have also verified the feasibility of sunlight-activated folding in space when vapour-deposited metallic coatings are applied onto the hinges. The proposed material o↵ers a new generation of gossamer space membrane that can automatically morph from a stowed configuration to a load-bearing structure, and potentially provide built-in functionalities.