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[Display omitted] • A morph-genetic biomimetic concept for fabricating zwitterionic hydrogels was proposed. • Macro-porous structures inside CTDPH matrix avoid the formation of salt crystallization. • The seawater evaporating rate of CTDPH increases to 3.11 kg m-2h−1 under 1-sun irradiation. • The CTDPH maintains 91.6% of its original solar evaporation rate even after 10 cycles. Huge seawater resources are of utmost importance in addressing the increasing and severe water shortage worldwide. However, high-efficiently and sustainably extracting fresh water from seawater through solar evaporation remains a challenging task. Herein, we propose a novel approach based on the morph-genetic biomimetic concept, utilizing a cuttlebone-templated directional porous hydrogel (CTDPH). By etching away the cuttlebone (CaCO 3) in the hydrogel network, we have developed a zwitterionic material that exhibits high-efficiency photo-thermal conversion, resistance to salt deposition, and super hydrophilicity, enabling high-efficiency solar evaporation. The resultant CTDPH demonstrates a high level of photo-thermal conversion efficiency, thanks to the incorporation of MXene (Ti 3 C 2 T x) 2D nanosheets. By introducing polyzwitterions into the hydrogel matrix, the CTDPH achieves superhydrophilicity, greatly enhancing the transport of seawater. More importantly, the CTDPH possesses a penetrating oriented macro-porous structure, enabling rapid seawater transportation while effectively preventing salt crystallization. This prevents salt deposition on the surface of the hydrogel even during continuous 12-hour 1.0 sun irradiation. As a result, compared with the MXene-free gels and cuttlebone-reserved gels, this CTDPH can largely increase the seawater evaporating rate from 0.73 or 1.75 to 3.11 kg m-2h−1 under 1.0 sun irradiation. Furthermore, even after undergoing 10 cycles of seawater evaporation, the CTDPH still maintains 91.6% of its original solar evaporation rate (2.85 kg m-2h−1). The CTDPH emerges as a promising contender, offering both high efficiency and sustainability for solar evaporation from seawater, while simultaneously paving the way for innovative approaches to explore other materials and systems in the realm of solar evaporation. [ABSTRACT FROM AUTHOR]

• Mercerization successfully controlled the dimensions of native BNC conduits. • Superior mechanical properties of BNC conduits were achieved via mercerization. • Mercerized BNC (MBNC) conduits exhibited nice hemocompatibility in absence of bioactive compounds. • MBNC conduits satisfied a long-term patency over 16 weeks in a rat abdominal aorta model. Bacterial nanocellulose (BNC) is a natural polysaccharide synthesized principally by Komagataeibatacter xylinus which can be formed into tubes and other shapes through the use of special bioreactors. Although tubular BNC has considerable potential as a small-caliber vascular graft (<6 mm), its poor mechanical properties in its hydrogel form, lack of compliance, and its thick walls that do not match natural vessels limit their potential clinical use and long-term patency rate after implantation. Mercerization is an approach in which an alkaline treatment changes the chemistry of BNC products. Following mercerization, tubular BNC grafts exhibited greater mechanical strength combined with thinner walls. Volumetric reduction of the tubular BNC was effective (by nearly 90%) when using a NaOH concentration greater than 10% (w/v), which caused fewer platelets to adhere to the luminal surface. Mercerized tubular BNC (MBNC) promoted the proliferation of endothelial cells in vitro. The MBNC obtained using 20% NaOH was selected for transplantation within a rat abdominal aorta model. Normal blood flow was observed for 16 weeks, indicating that the MBNC conduit maintained long-term patency. The results indicate that mercerization can control the size of tubular BNC and thus the MBNC conduit is a promising candidate for blood vessel replacement. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cyclic freezing-thawing approach to layered Janus hydrogel tapes with single-sided adhesiveness is developed. • The interfacial peeling force of the Janus hydrogel tapes reaches 114.6 N/m. • Strain sensors of Janus hydrogel tapes achieve a GF of 3.4. • Wireless wearable sensors based on Bluetooth signal transmission system are demonstrated. Hydrogel strain sensors, which have potential applications in wearable devices, soft robots and human–machine interfaces, etc., are increasingly investigated. But it remains challenging to fabricate hydrogel strain sensors with integrated wearability and high sensing performances. To address this issue, we herein propose a cyclic freezing-thawing approach to layered Janus hydrogel tapes for wearable strain sensors. The hydrogel tapes are composed of an adhesive poly(vinyl alcohol)/phytic acid (PVA/PA) layer and a non-adhesive poly(vinyl alcohol)/polyaniline (PVA/PANI) layer and exhibit controllable flexibility and approximate elastic modulus to soft tissues. A robust interface forms between the two layers and the interfacial peeling force reaches 114.6 N/m. Strain sensors assembled from the Janus hydrogel tapes achieve low response time (loading: 60 ms, unloading: 62 ms), reversible response and high sensitivity (gauge factor: 3.4). Interestingly, such strain sensors can be further integrated with a Bluetooth system to fabricate wireless wearable sensors for convenient monitoring of physiological activities such as walking, squatting, stair climbing, etc. Overall, this work will provide not only a new approach to Janus hydrogels, but also a new clue for developing functional flexible devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • An interconnected LIS hydrogel with self-tunable nanopore structure and flexibility is prepared. • LIS nanoparticles adjust the pore size and flexibility of the hybrid hydrogel. • The LIS porous hydrogel shows a super-high Li adsorption capacity in a marine environment. • The LIS porous hydrogel exhibits super-stable cyclic Li extraction performance. Li+ ion-sieve (LIS) films, foams, or granules have been fabricated to immobilize LIS to overcome powder loss for Li extraction from seawater. However, the practical application is still restricted by their low swelling ability and poor flexibility to withstand harsh marine environment for a long time. Here, a highly elastic interconnected porous LIS nanocomposite hydrogel with tunable pore structure and flexibility, as well as good swelling property, is prepared by using LIS (viz. λ-MnO 2) as a pore self-modifier during the in-situ fabrication of polypyrrole (PPy) and polyvinyl alcohol (PVA) interpenetrating hydrogel (denoted as λ-MnO 2 @IG). In addition to physical confinement interactions, the strong coordination/chelation and electrostatic interactions between λ-MnO 2 nanoparticles and polymer chains enable well-dispersed λ-MnO 2 nanoparticles to be confined in a rich network structure. Even at a marine environment (pH 8.3), the λ-MnO 2 @IG hydrogel exhibits superior Li+ adsorption performance (20.6 mg g−1 HMO), outperforming most adsorbents containing LIS. Specially, the porous hydrogel is easily recyclable and exhibits super-stable cyclic Li extraction performance, which are directly attributable to the further-improved pore structure in continuous regeneration process. This study provides a self-regulating strategy to design LIS porous hydrogels with controllable porosity, high flexibility, good swelling ability, and excellent cycle stability to address the growing Li+ demanding challenges. [ABSTRACT FROM AUTHOR]