Superlubricity has drawn substantial attention worldwide while the energy crisis is challenging human beings.Hence,numerous endeavors are bestowed to design materials for superlubricity achievement at multiple scales....Superlubricity has drawn substantial attention worldwide while the energy crisis is challenging human beings.Hence,numerous endeavors are bestowed to design materials for superlubricity achievement at multiple scales.Developments in graphene-family materials,such as graphene,graphene oxide,and graphene quantum dots,initiated an epoch for atomically thin solid lubricants.Nevertheless,superlubricity achieved with graphene-family materials still needs fundamental understanding for being applied in engineering in the future.In this review,the fundamental mechanisms for superlubricity that are achieved with graphene-family materials are outlined in detail,and the problems concerning graphene superlubricity and future progress in superlubricity are proposed.This review concludes the fundamental mechanisms for graphene superlubricity and offers guidance for utilizing graphene-family materials in superlubricity systems.展开更多
Graphene-oxide (GO) has been recognized as an excellent lubrication material owing to its two-dimensional structure and weak interlayer interactions. However, the functional groups of GO that can contribute to anti-fr...Graphene-oxide (GO) has been recognized as an excellent lubrication material owing to its two-dimensional structure and weak interlayer interactions. However, the functional groups of GO that can contribute to anti-friction, anti-wear, and superlubricity are yet to be elucidated. Hence, further improvement in GO-family materials in tribology and superlubricity fields is impeded. In this study, macroscale superlubricity with a coefficient of friction of less than 0.01 is achieved by exploiting the high adhesive force between amino groups within aminated GO (GO–NH_(2)) nanosheets and SiO_(2). It was observed that GO–NH_(2) nanosheets form a robust adsorption layer on the worn surfaces owing to the high adsorption of amino groups. This robust GO–NH_(2) adsorption layer not only protects the contact surfaces and contributes to low wear, but also causes the shearing plane to transform constantly from solid asperities (high friction) into GO–NH_(2) interlayers (weak interlayer interactions), resulting in superlubricity. A SiO_(2)-containing boundary layer formed by tribochemical reactions and a liquid film are conducive to low friction. Such macroscale liquid superlubricity provides further insights into the effect of functional groups within functionalized GO materials and a basis for designing functionalized GO materials with excellent tribological performances.展开更多
基金This work was financially supported by the National Key R&D Program of China(No.2020YFB2007300)the National Natural Science Foundation of China(No.52005287)+1 种基金the Foundation from State Key Laboratory of Tribology(Nos.SKLTKF20B01 and SKLTKF21B14)Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Superlubricity has drawn substantial attention worldwide while the energy crisis is challenging human beings.Hence,numerous endeavors are bestowed to design materials for superlubricity achievement at multiple scales.Developments in graphene-family materials,such as graphene,graphene oxide,and graphene quantum dots,initiated an epoch for atomically thin solid lubricants.Nevertheless,superlubricity achieved with graphene-family materials still needs fundamental understanding for being applied in engineering in the future.In this review,the fundamental mechanisms for superlubricity that are achieved with graphene-family materials are outlined in detail,and the problems concerning graphene superlubricity and future progress in superlubricity are proposed.This review concludes the fundamental mechanisms for graphene superlubricity and offers guidance for utilizing graphene-family materials in superlubricity systems.
基金the National Key R&D Program of China(Nos.2020YFB2007300,2020YFA0711003)the Foundation from State Key Laboratory of Tribology(No.SKLTKF20B01)+1 种基金Beijing Institute of Technology Research Fund Program for Young Scholars,the Fund of Key Laboratory of Advanced Materials of Ministry of Education(No.ADV21-4)the National Natural Science Foundation of China(No.52005287).
文摘Graphene-oxide (GO) has been recognized as an excellent lubrication material owing to its two-dimensional structure and weak interlayer interactions. However, the functional groups of GO that can contribute to anti-friction, anti-wear, and superlubricity are yet to be elucidated. Hence, further improvement in GO-family materials in tribology and superlubricity fields is impeded. In this study, macroscale superlubricity with a coefficient of friction of less than 0.01 is achieved by exploiting the high adhesive force between amino groups within aminated GO (GO–NH_(2)) nanosheets and SiO_(2). It was observed that GO–NH_(2) nanosheets form a robust adsorption layer on the worn surfaces owing to the high adsorption of amino groups. This robust GO–NH_(2) adsorption layer not only protects the contact surfaces and contributes to low wear, but also causes the shearing plane to transform constantly from solid asperities (high friction) into GO–NH_(2) interlayers (weak interlayer interactions), resulting in superlubricity. A SiO_(2)-containing boundary layer formed by tribochemical reactions and a liquid film are conducive to low friction. Such macroscale liquid superlubricity provides further insights into the effect of functional groups within functionalized GO materials and a basis for designing functionalized GO materials with excellent tribological performances.
