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Nowadays, hydrogels as flexible materials have attracted considerable attention in frontier fields such as wearable electronic devices, soft actuators and robotics. However, water-based hydrogels inevitably freeze at subzero temperatures and suffer damage from contact with objects, which greatly reduce their service life and practical value. Herein, nanocomposite hydrogels with self-healing performance at subzero temperatures were proposed by introducing binary water-glycerol continuous phase and dual self-healing interactions. The binary solvents were emphasized in preventing the formation of ice crystals, enhancing flexible and self-healing abilities of hydrogels in subzero environment. Linseed oil as healing agent was effectively loaded in Pickering droplets by cellulose nanocrystals. Owing to non-covalent bonding and external healing agent, the obtained hydrogels showed improved mechanical properties and self-healing abilities. Particularly, after incorporating Pickering droplets, the rupture stress of nanocomposite hydrogels was 0.24 MPa, the rupture strain was 1900% and the healing efficiency could be up to 80.1% for 12 h at − 20 °C. Therefore, the obtained hydrogels with frost resistance, stretchability and self-healing properties should have broader potential applications, especially in subzero environment.

This work aims to clarify the influence of texture type and intensity on the shape memory effect (SME) in NiTiNb shape memory alloy (SMA) pipe joints, especially revealing the causes for the anisotropy of SME via texture changes. Three NiTiNb rods with different intensities of the {111}&lt, 110&gt, texture were fabricated, and their microstructures, crystalline orientation distribution functions and inverse pole figures were obtained by X-ray diffraction and electron backscatter diffraction measurements. Simultaneously, the SME was characterized by inner-diameter recoverability of the corresponding pipe joints. For a given intensity of the {111}&lt, texture, the SME of the NiTiNb pipe joints strongly depended on the expansion direction due to {111}&lt, orientation-induced anisotropy of SME. In addition, both the SME and anisotropy of NiTiNb pipe joints increased with the increased intensity of the {111}&lt, texture. Therefore, a suitable expansion direction and strong texture intensity should be considered for high SME in NiTiNb pipe joints.