Investigation of nonreactive fluoroalkyl-containing surfactants for reducing release energy of ultraviolet-cured acrylate resins

Abstract

The authors investigated the types of additive nonreactive fluorinated surfactants that effectively decrease the release energy of a certain ultraviolet-cured base resin for radical photopolymerization. The release energies of resins containing various surfactants were compared in two atmospheres, namely air and 1,1,1,3,3-pentafluoropropane (PFP, HFC-245fa). Tridecafluoro-1,1,2,2-tetrahydrooctan-1-ol functioned as the most effective surfactant under an air atmosphere, for detachment of a silica surface modified with tridecafluoro-1,1,2,2-tetrahydrotrimethoxysilane from the cured resins. Under a PFP atmosphere, heptadecafluoro-1,1,2,2-tetrahydrodecan-1-ol with a longer fluoroalkyl chain was necessary to effectively decrease the release energy. It was indicated that the segregation of liquid fluoroalkyl alcohols between the cured resin and modified mold was effective in decreasing the release energy of cured resins.

Interfacial Interactions during Demolding in Nanoimprint Lithography

“…The remaining liquified condensable gas is assumed to remain as a thin PFP-rich layer between the mold and resist, or dissolves in the resist [ 34 , 36 ]. Since PFP contains fluorine and exhibits low surface energy, such a layer is suggested to effectively decrease the release energy (i.e., demolding force; see Figure 2 ) of the cured resist compared to that in air [ 34 , 36 , 37 , 38 ]. On the other hand, the use of condensable gas may be disadvantageous due to pattern height shrinking via absorption by the resist [ 39 ].…”

Surface modification of polyimide laser-drilled screen printing masks for low-viscosity liquids in print-and-imprint method

“…We have reported that laser-drilled screen printing with unmodified PI masks are applicable to (fluorescent) UVcurable liquids of NL-SK1(F) and NL-SU1(F) showing a viscosity of 12.8 and 11.0 Pa s, respectively, and a fluorescent glycerin showing a viscosity of 1.4 Pa s. 24,25,29) Here, we investigated whether the unmodified PI masks were available for a GDM-based UV-curable liquid with a low-viscosity of 0.10 Pa s to lower the range of viscosity applicable to laserdrilled screen printing. According to our previous study, 25) 100 through holes with a mean hole diameter of 9.3 μm on a substrate-contact-side surface were prepared with a pitch of 100 μm by laser drilling onto an area of 1.0 × 1.0 mm 2 of a PI film surface.…”

Discharge of viscous UV-curable resin droplets by screen printing for UV nanoimprint lithography

“…A commercially available silica mold (NTT-AT NIM-PH-350, 10 × 10 mm 2 ) with 350 nm-10 µm line-and-space, hole, and dot patterns was modified with tridecafluoro-1,1,2,2-tetrahydrooctyltrimethoxysilane (FAS13) as an antisticking agent by chemical vapor surface modification. 30) The UV nanoimprint process comprised five steps: (i) moving the fluorinated mold close to a thin resin film or resin droplets on a silicon substrate at a speed of 20 µm s −1 , (ii) increasing the applied pressure to 1.0 MPa, (iii) holding the position for load adjustment in 30 s, (iv) curing molded resin by exposure to UV light emitting from light-emitting diode arrays at a wavelength of 365 nm and a light intensity of 50 mW cm −2 for 20 s, and (v) demolding at a speed of 4,000 µm s −1 . Imprint resist patterns were observed by fluorescence microscopy under an optical microscope (Olympus BX51) equipped with a fluorescence cube (Olympus U-MWIG3, excitation wavelengths, 530-550 nm; detection wavelengths, >575 nm), an objective lens (Olympus UPlanS Apo 10×=0.40), and a charge-coupled device (CCD) camera (Hamamatsu Photonics ORCA-R2).…”