Chaotropic Ions Mediated Polymer Gelation for Thermal Management.

Energy and environmental issues have increasingly garnered significant attention for sustainable development. Flexible and shape-stable phase change materials display great potential in regulation of environmental temperature for energy saving and human comfort. Here, inspired by the water absorption behavior of salt-tolerant animals and plants in salinity environment and the Hofmeister theory, highly stable phase change salogels (PCSGs) are fabricated through in situ polymerization of hydrophilic monomers in molten salt hydrates, which can serve multiple functions including thermal management patches, smart windows, and ice blocking coatings. The gelation principles of the polymer in high ion concentration solution are explored through the density functional theory simulation and verified the feasibility of four types of salt hydrates. The high concentration chaotropic ions strongly interacted with polymer chains and promoted the gelation at low polymer concentrations which derive highly-stable and ultra-moisturizing PCSGs with high latent heat (> 200 J g-1). The synergistic adhesion and transparency switching abilities accompanied with phase transition enable their smart thermal management. The study resolves the melting leakage and thermal cycling stability of salt hydrates, and open an avenue to fabricate flexible PCM of low cost, high latent heat, and long-term durability for energy-saving, ice-blocking, and thermal management.

STEAP2 promotes osteosarcoma progression by inducing epithelial-mesenchymal transition via the PI3K/AKT/mTOR signaling pathway and is regulated by EFEMP2.

This study was designed to explore the prognostic significance and functionality of STEAP2 (six-transmembrane epithelial antigen of prostate 2) in osteosarcomas and determine whether EFEMP2 (Epidermal growth factor-containing fibulin-like extracellular matrix protein 2) targets STEAP2 to facilitate osteosarcoma cell infiltration and migration. STEAP2 expression in peritumoral tissues, osteosarcoma, benign fibrous dysplasia, osteosarcoma cells, normal osteoblastic hFOB cells, and various invasive subclones was evaluated using IHC, ICC, and qRT-PCR. We also evaluated the association between STEAP2 expression and disease outcome using Kaplan-Meier analyses and then investigated STEAP2 regulation and its functional effects using both in vitro and in vivo assays. The results revealed that the upregulation of STEAP2 in osteosarcoma tissues positively correlated with both the malignant osteosarcoma phenotype and poor patient outcomes. In addition, STEAP2 expression induced epithelial-mesenchymal transition (EMT) via the PI3K/AKT/mTOR axis and facilitated osteosarcoma cell infiltration and migration. Changes in EFEMP2 expression resulted in correlating changes in STEAP2 expression, with EFEMP2-overexpressing osteosarcoma cells exhibiting a less invasive phenotype and reduced EMT following STEAP2 inhibition. It is also worth noting that although EFEMP2 overexpression activated the PI3K/AKT/mTOR pathway promoting EMT, it did not affect osteosarcoma cells in which STEAP2 or Akt was knocked down. Thus, we can conclude that STEAP2 acts as an oncogene in osteosarcoma progression, while EFEMP2 enables PI3K/AKT/mTOR axis initiation and EMT by partly targeting STEAP2, thereby facilitating osteosarcoma cell infiltration and migration.

Shape-Stable Hydrated Salts/Polyacrylamide Phase-Change Organohydrogels for Smart Temperature Management.

Flexible and environmentally friendly phase-change materials (PCMs) with appropriate phase transition temperatures display great potential in the regulation of environmental temperature. Here, we synthesized a series of room-temperature-use phase-change organohydrogels (PCOHs) comprising phase-change hydrated salts (disodium phosphate dodecahydrate, DPDH) and polyacrylamide (PAM) glycerol hydrogels through a facile photoinitiated one-step in situ polymerization procedure. Incorporating the environmentally friendly cost-effective DPDH hydrated salts PCMs into antidrying three-dimensional (3D) networks of the PAM organohydrogel can overcome the solid rigidity and melting leakage to achieve flexibility for wearable temperature management devices. The microstructures and physical interactions among the components of the PCOHs were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD), which demonstrate that the DPDH were uniformly loaded in the networks of the PAM. Phase-change storage and thermal properties of the PCOHs were characterized by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and the PCOHs show high energy transition efficiency and shape stability during the long-term storage and thermal cycling. Dynamic rheology and compression tests demonstrate that PCOHs can withstand a certain stress and display flexibility performance even above the melting temperature of DPDH. We also described the smart temperature management capability and the potential application of the PCOHs. This investigation offers a facile method to construct a skin-friendly flexible phase-change glycerol hydrogel and provides an alternative to the traditional melt impregnation or microencapsulation method to prepare phase-change energy storage composites.

Transparent Stretchable Dual-Network Ionogel with Temperature Tolerance for High-Performance Flexible Strain Sensors.

A stretchable transparent double network ionogel composed of physically cross-linked poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)) and chemically cross-linked poly(methyl methacrylate-co-butylmethacrylate) (P(MMA-co-BMA)) elastomer networks within [EMIM][TFSI] ionic liquid was fabricated through a facile one-pot thermal polymerization. The dual-network (DN) ionogel presents good mechanical performance (failure tensile stress 2.31 MPa, strain 307%) with a high loading of ionic liquid (70 wt %) for achieving required ionic conductivity (>0.1 S/m at room temperature). The transparent chemical cross-linked P(MMA-co-BMA) elastomer network endows high transparency (>93%) and high stretchability to the DN ionogel. The DN ionogel maintains good toughness, elasticity, and transparency in a wide temperature range (-40 to 80 °C) for the application in a harsh environment. In addition, the sensitivity of the DN ionogel to the change of environment temperature and deformation was detected and described. The practical potential of the DN ionogel in flexible electronic devices is further revealed by fabricating DN ionogel strain sensors to detect the movement of different human limbs including the bending of the finger, wrist, and elbow as well as the slight throat jitter during the swallowing and vocalization, showing fast response, high sensitivity, and good repeatability.