Extreme UV Radiation Grafting of Glycidyl Methacrylate Nanostructures onto Fluoropolymer Foils by RAFT-Mediated Polymerization

Abstract

Periodic nanostructures of poly(glycidyl methacrylate) (pGMA) were grafted onto poly(ethylenealt-tetrafluorethylene) (ETFE) films by reversible addition-fragmentation chain transfer (RAFT) polymerization. ETFE samples were first irradiated in an interference lithographic setup using EUV (extreme ultraviolet) light followed by exposure to air to introduce surface peroxide groups serving as thermal initiators for the graft polymerization. The dependence of height and morphology of the grafted pGMA structures on the exposure dose and on the grafting parameters such as time and concentration of RAFT chain transfer agent was studied with atomic force microscopy (AFM) and scanning electron microscopy (SEM). RAFT mediation reduces the grafted layer thickness by a factor of 5-10 compared to uncontrolled free radical polymerization and significantly improves the spatial resolution into the 50 nm range. A mushroom to brush transition was observed for low absorbed doses. This transition was found to occur at ∼(1.5 ( 0.7) × 10 -3 and ∼(3 ( 1.3) × 10 -3 chains/nm 2 for the free radical and RAFT-mediated polymerization, respectively. The grafting density increased with increasing absorbed dose up to a maximum of 0.1-0.2 chains/nm 2 . The data interpretation is supported by simulations based on photon statistics.

Radiation-grafted materials for energy conversion and energy storage applications

“…Chemical and mechanical stability of these new ETFE-based membranes appeared to be promising since it was tested for more than 2000 h in the DMFC without any significant loss in performance. [130,[165][166][167][168]. Subsequently, an irradiated substrate is exposed to a monomer solution to perform polymerization from the backbone.…”

Extreme ultraviolet interference lithography at the Paul Scherrer Institut

“…Improvements in the resolution down to the 50 nm range are possible by applying "living-radical" polymerization schemes, which limit the chain growth kinetics, or by postprocessing steps such as thermal or solvent annealing. 72 The firm anchoring of the grafted polymer chains enables various chemical derivatization reactions of the grafted chains, including biofunctionalization, e.g., by binding specific protein molecules. For example, the formation of biofunctional and thermoresponsive polymer brush structures has been demonstrated ͑Fig.…”

Microwave initiated synthesis of polyacrylamide grafted Psyllium and its application as a flocculant

“…There is always a strong probability of radiation damage (radiolysis) to the polysaccharide backbone [14][15][16][17][18][19]. This method is perfectly fit for synthesis in case of fluoro-polymers, which are exceptionally stable [20][21][22]. Moreover, this also involves working with hazardous radiations and needs to be handled with utmost care with all precautions.…”