Hot Embossing of Micro-Pyramids into Thermoset Thiol-Ene Film

Abstract

This paper presents the first attempt to texturize a fully crosslinked thermoset shape memory polymer using a hot embossing technique. UV-cured thiol-ene films were successfully embossed with anisotropically-etched Si (100) stamps at a temperature of 100 °C, which is about 50 °C above the glass transition temperature of the polymer. The low storage modulus of the polymer in a rubbery state allowed us to permanently emboss random micro-pyramidal patterns onto the surface of the film with high fidelity by applying 30 MPa pressure for 1 h. Atomic force microscopy (AFM) investigation showed perfect replication of the stamp micropattern with typical height of the largest inverted pyramids close to 0.7 µm and lateral dimensions in the range of 1–2 µm. Changes in surface roughness parameters of the embossed thiol-ene films after annealing them at 100 °C for 1 h or storing for 2 months in air at standard room conditions were negligible. The achieved results open new perspectives for the simple and inexpensive hot embossing technique to be applied for the micropatterning of prepolymerized thermoset shape memory films as an alternative to micropatterning using UV casting.

Trilayer Composite System Based on SiO2, Thiol-Ene, and PEDOT:PSS. Focus on Stability after Thermal Treatment and Solar Irradiance

“…Only minor scratches were observable after the healing process of the thermally treated and irradiated trilayers ( Figure 4 b,c), indicating excellent shape-memory assisted scratch-healing stability of the fabricated trilayer composite. This finding is consistent with the results of previous studies, showing excellent scratch-healing, shape fixity, and recovery properties of this particular composition of PETMP-TTT [ 19 , 20 , 32 ].…”

Current and Future Trends for Polymer Micro/Nanoprocessing in Industrial Applications

“…[91,92] A fully crosslinked thermoset shape-memory polymer was texturized using hot embossing, and the typical height of the largest inverted pyramids was ≈0.7 µm. [93] Based on hot embossing, Bao et al fabricated stretchable, biocompatible, and biodegradable sensors [68] Copyright 2010, Springer Nature. b) Schematic of thermoforming to produce PMMA microspheres.…”

Electrical Characterization of Thin PEDOT:PSS Films on Alumina and Thiol–Ene Substrates

“…In a previous work, we fabricated and tested highly optically transparent thiol-ene coatings capable of healing scratches under room-temperature conditions [36]. These coatings can be permanently microstructured by UV casting or hot embossing, and are capable of recovering mechanically deformed surface microstructures after heat treatment above the glass transition temperature of the polymer [37,38]. Recently, we reported on the fabrication of PEDOT:PSS and thiol-ene bilayers for optoelectronic applications, and described the initial results on the measurements of the mechanical and optical properties of such composite films [39].…”