Direct Nanoimprint Lithography of Polyethersulfone Using Cellulose‐Based Mold

Abstract

and resist materials were investigated for the expanded nanoimprint lithography and application of biomass resources. [21][22][23][24][25] Herein, high-accuracy nanopatterning of PES using dimethylformamide as a dilution solvent was obtained by direct thermal nano imprint lithography using the newly modified solvent-permeable cellulosebased mold.In summary, the 900-nm line pattern failure of PES containing dimethylformamide as a dilution solvent was solved using the solvent-permeable cellulosebased mold. The direct nanoimprint lithography using the new solvent-permeable mold and solvent-mixed super-engineering plastics has realized the surface nanostructures of PES. Experimental SectionThe structures of a) hydroxypropyl cellulose with thermally cross-linked acryloyloxyalkyl groups in the solvent-permeable cellulose-based mold, b) 2-hydroxy-2-methylpropiophenone as an ultraviolet(UV) initiator, c) azobisisobutyronitrile as a thermal initiator, d) polyethersulfone, e) dimethylformamide as a dilution solvent with high solubility for increasing the fluidity of PES, f) novolac derivatives with hydroxyl groups to react with the cross-linker to improve adhesion to polyethersulfone during the imprinting process, g) 1,3,4,6-tetrakis(methoxymethyl) glycoluril as a cross-linker, and h) pyridinium p-toluenesulfonate as an initiator are shown in Figure 1.2-Methacryloyloxyalkyl isocyanate was reacted with hydroxypropyl cellulose to add thermally cross-linked acryloyloxyalkyl groups into the hydroxypropyl cellulose to prepare the solvent-permeable cellulose-based mold. The resulting chemical reaction between 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose was evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. [26][27][28] Methyl ethyl ketone was blended with 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose. The content of 2-methacryloyloxyalkyl isocyanate and hydroxypropyl cellulose in the solution was 26 wt%. The solution was stirred under a nitrogen atmosphere at 63 °C for 2.5 h, after adding triethylamine with a concentration of 7.9 wt% to the solution. Gel-permeation chromatography (HLC-8320GPC, Tosoh) was used to obtain the molecular weight of solvent-permeable cellulosebased mold. The solvent-permeable cellulose-based mold with an average molecular weight of 53 000 relative to a polystyrene standard was developed. The solvent-permeable cellulose-based mold with thermally cross-linked acryloyloxyalkyl groups was formulated with the following concentrations: 95 wt% of cellulose derivative, 2.5 wt% of 2-hydroxy-2-methylpropiophenone, and 2.5 wt% of azobisisobutyronitrile as a thermal initiator.The adhesion underlayer material on substrates, such as stainless mesh plate and silicon wafer was prepared to provide an adhesion between the substrates and patterning materials, such as PES and solvent-permeable cellulose-based mold, thereby reducing the pattern Polyethersulfone (PES) with a glass transition temperature of 224 °C is a class of high-performance super engi...

Recent progress of patterned electrodes in wearable electronics: fabrication and application

“…In these years, thermal nanoimprint and UV-assisted nanoimprint are mainly investigated. Satoshi Takei has fabricated highaccuracy 900 nm line patterning of PES using thermal nanoimprint lithography [83]. Polymethyl methacrylate (PMMA) is often used as transferring media in thermal nanoimprint lithography as it has good thermoplasticity.…”

Plant‐Based Structures as an Opportunity to Engineer Optical Functions in Next‐Generation Light Management

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Fabrication Technology of Self-Dissolving Sodium Hyaluronate Gels Ultrafine Microneedles for Medical Applications with UV-Curing Gas-Permeable Mold

“…We previously reported the fabrication of self-dissolving hyaluronic acid ultrafine microneedles under heating conditions using nanoimprint lithography, a form of micromolding that employs a heat-curing TiO 2 -SiO 2 gas-permeable mold [43]. Gas-permeable molds could improve the molding defects caused by trapped gas by making the molds porous [44,45]. However, since this method requires vacuum drying at 40 • C, there were concerns that the drug would decompose, especially for heat-sensitive substances such as insulin and vaccines [46].…”