Recently, flexible wearable and implantable electronic devices have attracted enormous interest in biomedical applications. However, current bioelectronic systems have not solved the problem of mechanical mismatch of tissue–electrode interfaces. Therefore, the biomimetic hydrogel with tissue-like mechanical properties is highly desirable for flexible electronic devices. Herein, we propose a strategy to fabricate a biomimetic hydrogel with strain-stiffening property via regional chain entanglements. The strain-stiffening property of the biomimetic hydrogel is realized by embedding highly swollen poly­(acrylate sodium) microgels to act as the microregions of dense entanglement in the soft polyacrylamide matrix. In addition, poly­(acrylate sodium) microgels can release Na+ ions, endowing hydrogel with electrical signals to serve as strain sensors for detecting different human movements. The resultant sensors own a low Young’s modulus (22.61–112.45 kPa), high nominal tensile strength (0.99 MPa), and high sensitivity with a gauge factor up to 6.77 at strain of 300%. Based on its simple manufacture process, well mechanical matching suitability, and high sensitivity, the as-prepared sensor might have great potential for a wide range of large-scale applications such as wearable and implantable electronic devices.

In this work, polyurethane (PU) materials containing paraffin oil are successfully prepared via an emulsion template method, which realizes the one‐pot preparation of self‐lubrication materials. The results show that the block copolymer surfactant (PEG20‐PPG70‐PEG20, P‐123) can stabilize the nonaqueous PU emulsion with the paraffin oil serving both as dispersed phase of oil in oil emulsion and as a lubricant in the materials, and hence enables the fabrication of oil incorporating PU materials accordingly. Tribological tests show that the friction coefficient of PU material with 35% paraffin oil decreases to 0.05 which account for 93.06% reduce compared to that of pure PU.

Self-lubricating composite with stimuli-responsive properties attracts great interest in recent years. Herein, mesoporous silica (MS) as oil-laden containers is explored to achieve self-lubricating feature. The as-prepared MS possesses a high Brunauer-Emmett-Teller (BET) surface area (1,542.35 m 2 /g), which satisfies the criterion for construction of ideal repository for storing enough liquid lubricants. In addition, the thermal stimuli-responsiveness behavior of the oil-laden mesoporous silica (OMS) for lubrication has been investigated by thermogravimetric analyzer tester. As expected, an excellent tribological performance (friction coefficient and wear rate decreased by 63.29 and 82.63%) is obtained by adding 10 wt% OMS into the polyurathene matrix, showing great promise for self-lubricating application.

As a type of material with high porosity exhibiting emerging potential in tribology application, polyimide aerogels (PIA) with different crosslinkers (tris­(4-aminophenyl) amine (TAPA) and 1,3,5-tris­(4-aminophenyl) benzene (TAPB)) and different crosslinking degrees were synthesized. The geometry configuration of crosslinkers has a remarkable influence on the morphology/physical properties of PIA including the shrinkage of PIA fabricated with TAPA being more evident and inverse phenomenon being illustrated for the porosity result. Also, the crosslinkers improve the mechanical properties significantlythe modulus of TAPA-PIA-3 reaches up to 14.21 MPa. Meanwhile, crosslinked PIA under dry sliding generally have lower wear rates compared with linear PIA whereas TAPA-PIA incorporating a lubricant have excellent tribological properties with the wear resistance increased by 69.52% and the friction coefficient reduced by 43.72%. Besides the anxo-action of the chain rigidness imparted by TAPA, the non-coplanarity of TAPA contributes to more compact entanglement and stacking of PIA molecules, which both improve the tribological properties correspondingly.