Spatial configuration has a significant effect on chemical self-assembly.However,the importance of spatial configuration in supramolecular adhesive materials has been frequently ignored.In this study,the effects of th...Spatial configuration has a significant effect on chemical self-assembly.However,the importance of spatial configuration in supramolecular adhesive materials has been frequently ignored.In this study,the effects of the spatial configuration on cohesion and adhesion were investigated.Owing to the diversities of the chemical structures and assembly patterns,1,2-disubstituted cyclohexane derivatives were used in this combined experimental and theoretical investigation.The self-sorting assembly of enantiopure isomers improved cohesion but had a negative effect on adhesion.In contrast,racemic mixtures displayed stronger adhesion effects.Moreover,it was proven that the cis-configuration was more favorable for supramolecular adhesion than the trans-counterpart.In addition,the influence of the spatial configuration of 1,2-disubstituted cyclohexane derivatives could be effectively mitigated by hydrogen bond donors or acceptors.The addition of natural acids yielded three-dimensional polymeric networks,in which the spatial configuration was not the decisive factor for supramolecular adhesion.展开更多
Insulated polyimide(PI)composites filled with short glass fibers(SGF),polytetrafluoroethylene(PTFE),SiO2,and polyphenylene(PPL)are specially designed,prepared,and the tribological properties are systematically investi...Insulated polyimide(PI)composites filled with short glass fibers(SGF),polytetrafluoroethylene(PTFE),SiO2,and polyphenylene(PPL)are specially designed,prepared,and the tribological properties are systematically investigated with references to the special requirements for frictional materials used in ultrasonic motors.The hardness and thermal decomposition temperature of the insulated PI composites are comparable to that of conductive PI composites.However,these insulated materials present excellent friction and wear performance,especially under high loads and speeds.Scanning electron microscopy(SEM)analysis of the worn surface indicates that adhesive and fatigue wear dominate the wear mechanisms.展开更多
基金The authors gratefully acknowledge the Outstanding Youth Scientist Foundation of Hunan Province(No.2021JJ10010)the National Natural Science Foundation of China(Nos.22271087,21704024)+1 种基金the Huxiang Young Talent Program from Hunan Province(No.2018RS3036)the Fundamental Research Funds for the Central Universities from Hunan University.
文摘Spatial configuration has a significant effect on chemical self-assembly.However,the importance of spatial configuration in supramolecular adhesive materials has been frequently ignored.In this study,the effects of the spatial configuration on cohesion and adhesion were investigated.Owing to the diversities of the chemical structures and assembly patterns,1,2-disubstituted cyclohexane derivatives were used in this combined experimental and theoretical investigation.The self-sorting assembly of enantiopure isomers improved cohesion but had a negative effect on adhesion.In contrast,racemic mixtures displayed stronger adhesion effects.Moreover,it was proven that the cis-configuration was more favorable for supramolecular adhesion than the trans-counterpart.In addition,the influence of the spatial configuration of 1,2-disubstituted cyclohexane derivatives could be effectively mitigated by hydrogen bond donors or acceptors.The addition of natural acids yielded three-dimensional polymeric networks,in which the spatial configuration was not the decisive factor for supramolecular adhesion.
基金This work is supported by the Fundamental Research Funds for the Central Universities(NS2018010)the Major State Basic Research Development Program of China(973 Program,Grant No.2015CB057501)。
文摘Insulated polyimide(PI)composites filled with short glass fibers(SGF),polytetrafluoroethylene(PTFE),SiO2,and polyphenylene(PPL)are specially designed,prepared,and the tribological properties are systematically investigated with references to the special requirements for frictional materials used in ultrasonic motors.The hardness and thermal decomposition temperature of the insulated PI composites are comparable to that of conductive PI composites.However,these insulated materials present excellent friction and wear performance,especially under high loads and speeds.Scanning electron microscopy(SEM)analysis of the worn surface indicates that adhesive and fatigue wear dominate the wear mechanisms.
