Study On Fabrication And Properties Of Poly(Urethane Acrylate) (PUA) Moth Eye Structure

Moth-eye structure is one kind of nanopillar array with high aspect ratio, and has wide application prospect on display technology and bionic fields for its good optical transparency and super hydrophobic. In this paper, the Poly(urethane acrylate) (PUA) was cast onto anodized aluminum oxide (AAO) template and can be successfully transferred from the template to Polyethylene terephthalate (PET) after surface modification and UV curing. The properties of antireflection and super hydrophobic of PUA moth-eye structure were tested, and its application on glucose detection and nano-imprint lithograph (NIL) were discussed. The detailed work is listed as follows:(1) Process optimization and structural properties. To optimize the fabrication process, the adhesion energy difference among the AAO template, PUA and PET were analyzed, and the C=C double-bonded conversion level was applied to measure the curing rate of the PUA. The moth-eye structure with large area was replicated successfully and the defect issues such as collapses and fracture were not observed for the use of the surface modification on PET and optimized curing conditions. The PUA moth-eye structure is equivalent to the structure composed of multiple layers with different refractive index optical antireflection film, and its transmission efficiency is increased significantly compared to the PET film with bare flat surface. The mechanism of super hydrophobic was discussed. The contact angle between the moth-eye structure modified by DC2634 and water was measured to be over 150 degree, which indicates low surface energy and slender nanostructure are beneficial to obtain super hydrophobic surface.(2) The applications of PUA moth-eye structure. Surface Enhanced Raman Scattering (SERS) of the glucose molecule was observed on the silver thin film substrate with moth-eye structure. The 200nm cycle PUA moth-eye structure can be taken as the template of the NIL to obtain Polymethyl methacrylate (PMMA) moth-eye structure, and the key factors of NIL were discussed.This progress for the fabrication of moth-eye structure should be found broad applications in the field of optical antireflection and bioinstrumentation.