Preparation Of Colloidal Probes By Bidirectional Method And Application Of Probes

With the further development of nano-tribology,colloidal probe has many advantages,such as stable composition of spherical tip,excellent mechanical properties,strong anti-interference ability,not easy to damage the sample surface,and accurate analysis of contact area,which make up for the application limitations of ordinary AFM probe in many fields.It has promoted its application and development in many fields such as material science,tribology,mechanics,physics and biomedicine.In this paper,a simple,easy to operate and high success rate of preparation of physical adhesion method--bidirectional method is proposed.By inverting the glass slide containing microspheres and moving the probe and microspheres,the difficult problem that has troubled the preparation technology of microspheres for many years is solved.The actual preparation platform was built and optimized and upgraded according to the defects of the preparation.The precise positioning of microspheres on the cantilever,the amount of glue on the cantilever and the position of glue drops could be accurately controlled,and a high-quality colloidal probe could be prepared every 5 minutes.In order to achieve high quality control of the colloidal probe,multiple characterization tests were used in this paper: initial forward side detection by microscope,side detection by SEM and AFM reverse imaging tip characterization.The pollution degree of the tip was classified in detail.They can reduce the experimental error caused by the factor of probe quality,and significantly improve the reliability and stability of experimental data.Based on the application of AFM,the effect of probe size on adhesion force and friction on graphene surface was studied.According to the experimental results and theoretical analysis,it is found that the adhesion force and friction force increase with the increase of the tip size of the probe,and it is found that the number of graphene layers has a weak effect on the surface adhesion force.During the experiment,it was found that when one or less layers of graphene were attached to the surface of the tip,the friction force and friction coefficient were far lower than the normal level,and the friction coefficient could reach as low as 0.003,belonging to ultra-low friction.Based on the original bidirectional preparation platform and PDMS membrane,the ultra-low friction microsphere probe with graphene on the surface was actively prepared.The further study of ultra-low friction will definitely promote the development of micro friction theory and lay a solid foundation for its application to macro friction theory in the future.