Replicate Technique And Applications Of Micro-Nano Structures Based On Flexible Substrate

Micro/nano structures based on flexible substrate show good physical and chemical properties, especially for polymer substrate. They are widely used in optics, electronics, biological and medical fields as they can achieve better bio-compatibility, electrical and thermal insulation than that of the Si substrate. The replication technique of the batch and low cost fabrication is the most important method for the development and application of the flexible substrate devices.This thesis takes the flexible materials as the research object. Surrounding the work of adhesion based on surface energy and the Dynamic Nano-inscribing technology based on viscoelastic property, this dissertation carried out the research of transfer printing, reversal thermal bonding, flexible reversal soft UV nanoimprint and dynamic nano-inscribing technologies, and research of simulations, applications, such as the fabrication of solar cell electrode, controlled nano channels and so on, combined with conventional and unconventional micro/nano fabrication methods. The main research contents and contributions of this thesis are listed as follows:(1) We figured out the mechanism of micro/nano fabrication based on the work of adhesion. The solid surface wettability was studied to help us work out the work of adhesion by measuring the contact angle and liquid surface tension. Transferring printing technology and its applications was studied and the process concerned such as casting, stamping and printing was researched to optimize the parameters by both simulation and experiment. Using the transfer printing technology, a set of production process for silver electrode was developed.(2) Using reversal thermal bonding technology to fabricate nanochannels can solve the challenge of low bonding adhesion and how to control the nanochannels size precisely. We achieved the free-standing SU-8structure sheet, which was then covered onto the other thin polymer film boding followed by pressure and capillary force. Instating of using the SU-8structure as the substrate we achieved the free-standing SU-8structure sheet that used as the bonding layer.(3) The flexible reversal UV casting technique was figured out to fabricate the high aspect ratio polymer patterns and the difficulty of release failure caused by large contact area was overcome based on work of adhesion and the flexible substrate. We monitored the C=C double-bonded conversion level in token of the curing rate of the substrate material PUA to overcome the challenge of collapses and achieved high desity, high aspect ratio subwavelength gratings for visible region successfully. The anti-reflection effect was designed and experimental verificated. What’s more, the effect of SERS (Surface Enhanced Raman Spectroscopy) on subwavelength structures was also verificated.(4) The DNI (Dynamic Nano-inscribing) technique for making continuous large area patterns on flexible substrate was validated by both theory and experiments. In order to study the process of DNI from the microscopic perspective, the DNI simulation model of varied substrates was founded and the dependency between depth and property of the materials, temperature, speed, pressure was discussed. We set up a DNI device in the lab both and the control system of the speed, press and temperature. The relationship of temperature, speed and depth was also verificated. We applied the DNI technique to the fabrication of subwavelength structures and nanochannels successfully.