Atmospheric Aerosol Assisted Pulsed Plasma Polymerization: An Environmentally Friendly Technique for Tunable Catechol-Bearing Thin Films

Abstract

In this work, an atmospheric aerosol assisted pulsed plasma process is reported as an environmentally friendly technique for the preparation of tunable catechol-bearing thin films under solvent and catalyst free conditions. The approach relies on the direct injection of dopamine acrylamide dissolved in 2-hydroxyethylmethacrylate as comonomer into the plasma zone. By adjusting the pulsing of the electrical discharge, the reactive plasma process can be alternatively switch ON (t ON ) and OFF (t OFF ) during different periods of time, thus allowing a facile and fine tuning of the catechol density, morphology and deposition rate of the coating. An optimal t ON /t OFF ratio is established, that permits maximizing the catechol content in the deposited film. Finally, a diagram, based on the average energy input into the process, is proposed allowing for easy custom synthesis of layers with specific chemical and physical properties, thus highlighting the utility of the developed dry plasma route.

A Review of Plasma Synthesis Methods for Polymer Films and Nanoparticles under Atmospheric Pressure Conditions

“…Materials in a gaseous state at room temperature are themselves applied as precursors, whereas materials that exist as liquids are mainly introduced to a plasma region as an aerosol via atomizing or bubbling with gas. GATP methods are commonly used for the deposition of polymer films [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 ], as this method allows in-line processing by moving either the APP devices or the substrates [ 39 ].…”

Recent Advancements in the Use of Aerosol-Assisted Atmospheric Pressure Plasma Deposition

“…J. Profili et al compared coatings deposited from atomized HMDSO with and without TiO 2 and they found, as expected, a rough surface (R rms in the range 32-60 nm) when NPs where present in the feed, but the morphology was also influenced by source voltage waveforms [60]. V. Jalaber et al demonstrated that the duty cycle of a pulsed source can be controlled to tune the morphology of catechol-containing films [80].…”

Plasma and Polymers: Recent Progress and Trends

“…The properties of the resultant polypyrrole self-supporting thin films (e.g., their thickness, conductivity, and roughness) were determined by operating parameters such as discharge length and intensity, flow of processing argon gas, and the presence of nitrogen gas. The mechanism of polymer formation under these conditions is significantly different from that on the solid surface from volatile precursor, and to that during atmospheric aerosol assisted pulsed plasma polymerization [ 86 ]. Briefly, the collisions between plasma-generated electrons and N 2 molecules in air results in the generation of nitrogen-containing species including free radicals, some of which reach the interfacial layer between the gas and liquid phases, diffusing across this layer into the microemulsion.…”