"It is challenging to experimentally determine the micro-friction mechanism of cotton fiber and metal in the sliding process. The influence of load and temperature on the interface behavior during dry friction between amorphous cotton fiber and chromium, the contact interface evolution and friction coefficient are studied using reactive molecular dynamics. The simulation results show that chromium–oxygen bonds are formed on the contact interface of the friction system during the sliding process. Furthermore, the relationship between friction coefficient, temperature, and load varies with the mechanical state of cotton cellulose. The relationship is positive when the cotton cellulose is in the glassy state. However, when cotton cellulose is in a highly elastic state, its friction coefficient is negatively related to the load. This study systematically evaluated the effects of temperature and load on the slip process from the atomic scale, provided a reason for the wear of the hard materials of the friction pair, and provided theoretical support for the study of this type of friction mechanism."

No abstract

This study investigates the influence of sliding velocity and loading on the friction of chromium and amorphous cotton fibers using water molecules act as lubricants via molecular dynamics simulation. It is found that the movement of water molecules between the contact interfaces is mainly along the sliding-direction not than the loading-direction during the sliding process. The high sliding velocity or large loading will reduce the lubricating properties of water molecules and increase the average coefficient of friction in the stabilization. The sliding time before the stabilization increase with sliding velocity while decreases with loading. Moreover, the water-lubricants can reduce the damage to chromium, and the increase of sliding velocity is more easy to cause the damage than loading, so it is more important to choose a right sliding velocity.

Ionic hydrogel thermoelectric generators (ITEGs) are becoming increasingly popular in effective recovery of low-grade waste heat, but they suffer from relatively low output power density and energy density. In this work, by utilizing the synergetic strategy of thermodiffusion effect and redox reaction on electrodes, an ITEG is demonstrated which demonstrates impressive thermoelectric conversion properties. On the one hand, an interpenetrating network structured ionic gel with temperature-sensitive phase transition behavior is designed as thermoelectric material to achieve a very high thermopower of 40.60 mV K −1 at a temperature gradient (𝚫T) of 5 K. On the other hand, polymer redox polyaniline (PANI) is appended on the carbon weaved fabric (CWF) electrode to augment heat-to-electricity storage and output power performance. It is found that the PANI@CWF electrode assists to realize a larger current density output, 1 h output energy density (E 1h ) (570 J m −2 ) at a 𝚫T of 20 K and a maximum normalized instantaneous output power density of 11.31 mW m −2 K −2 are obtained, which is a record-breaking result among the reported quasi-solid-state ITEGs. A feasible routine to design the top-performing ITEGs is verified, which shows commercial promise for continuously powering electronic devices such as sensors and wearable electronics.