UV LED Curable Perfluoropolyether (PFPE)-Urethane Methacrylate Transparent Coatings for Photonic Applications: Synthesis and Characterization

Abstract

The contribution aims to bring forth a novel synthesis route in developing transparent UV LED-curable coatings accounting for various exposure options. A selection of perfluoropolyether (PFPE)-urethane methacrylate and acrylate resins, free-radical photo-initiator Omnirad 2100, and two distinct silane-based crosslinking agents were blended under a weight ratio of 75:20:5 (without crosslinker) and 70:15:5:10, respectively. The coatings were cured under a UV LED 4 × 3 matrix light emitting source, in a chamber under a controlled atmosphere, by means of an in-house developed conveyor belt type platform, at different conveyor belt speeds (5, 50, 150, 250, and 500 mm/s). The morphologies of fabricated coatings were characterized by FTIR revealing high conversion rates (e.g., from 98 to 100%) for increased exposure time as a result of the 5 or 50 mm/s values, on all combinations. Dynamic–mechanical and optical properties of UV LED-cured transparent coatings were also investigated. A negative shift of the glass transition temperature values with a decrease in exposure time, in all combinations, from about 60 °C to 30 °C, along with storage moduli lowering in the glassy plateau further favors higher exposure times for curing. The refractive indices of poly-mers were from 1.38 to 1.40, whereas the thermo-optic coefficients are showing minor changes around the value of 2.55∙10−4 K−1.

Surface Activity, Wetting, and Aggregation of a Perfluoropolyether Quaternary Ammonium Salt Surfactant with a Hydroxyethyl Group

“…Fluorocarbon surfactants are special surfactants in which the introduced fluorine atom partially or completely replaces the hydrogen in the hydrophobic chain of the hydrocarbon surfactant to form a hydrophobic portion consisting of a fluoroalkyl or alkenyl group [3]. Unlike traditional hydrocarbon surfactants, fluorocarbon surfactants are widely used in firefighting [4], oil extraction [5,6], and electronics [7,8], and for manufacturing paper [9] and coatings [10,11], due to their excellent physicochemical properties, including high surface activity, thermal and chemical stability, and water and oil repellency [12,13].…”

To Shed Light on the UV Curable Coating Technology: Current State of the Art and Perspectives

“…The first system is the LED cure. LEDs are commercially available lamps, and many studies have been published on LED curing [22,79,[129][130][131][132]. As discussed before, its low energy consumption, low heat generation, low cost and long life have gained huge attention worldwide.…”