Carbon Nanotube Array:Synthesis,Contact/Tribo-charge And Adhesion

Vertically aligned carbon nanotube arrays(VACNT)are structurally similar to gecko setae arrays,and CNTs have excellent mechanical,electrical,and chemical stability,so VACNT has become a potential bionic adhesive.In this paper,VACNT was grown on the metal substrate based on the contact electrification of gecko feet.The effects of electrostatic interaction on adhesion during the adhesion process of VACNT adhesive were studied by experimental verification and theoretical analysis.The main results and conclusions of this paper are as follows:1.Preparation of CNTs on the surface of stainless steel and Inconel substrate by direct growth method and coating growth method.The quality of CNTs prepared by the direct growth method is better than that of the coating growth method,and the quality of CNTs on the surface of stainless steel substrate is better than that of the Inconel substrate.The thickness of the stainless steel substrate is positively related to the height and quality of the prepared VACNT.The deposition of CNTs on the surface of the substrate can cause bending deformation of the ultra-thin metal substrate,the bending deformation can be suppressed by methods of pre-bending treatment or double-sided deposition.2.VACNT-PTFE has contact electrification and can produce a stable voltage output during the contact separation process.Different substrates affect the voltage amplitude.Set up a platform to collect the charge generated during the contact adhesion process of VACNT-PTFE.The adhesion strength of VACNT is related to the number of repetitions.The possible effects of external electric field on VACNT adhesion are covered by the effects of repeated adhesion.In the macro experiment,there is no obvious correspondence between the adhesion strength of the adhesive based on van der Waals and the change of the external electric field.3.The point contact model was used to analyze the Coulomb force and van der Waals force between the charged VACNT and the target surface.The adhesion force was positively related to the density of VACNT.The potential distribution during the contact-separation process of VACNT-PTFE was simulated,and it was found that the potential difference between VACNT and PTFE increased with the increase of the distance.Calculate the tip aggregation effect of VACNT.When the length and diameter are constant,there is an optimal array density to maximize the tip electric field.Based on the influence of the external electric field on the intermolecular dipole moment,the degree of influence of the external electric field on the orientation of van der Waals was analyzed.