Exploring molecular-level rolling friction based on cyclodextrins for lubrication

The minimization of friction through the replacement of sliding with rolling friction is well-established in macroscopic applications, yet achieving this objective on the molecular scale has proven elusive. Herein, we report a novel strategy for molecular-level rolling friction that utilizes the molecular rolling effect of cyclodextrins to supplant the traditional sliding mechanism. This approach aims to vastly improve the lubricity and wear resistance of synthetic biofriction materials. The use of biocompatible α-cyclodextrin molecules as "rings" within polyrotaxane networks yields significantly reduced friction coefficients and wear rates compared to commercial Ti₆Al₄V alloys and control systems without such rings. This research introduces a novel approach to designing, constructing, and optimizing diverse friction materials and highlights the immense potential of molecular-scale engineering to revolutionize traditional materials and propel friction science and molecular technology to new frontiers.