Chemical Vapor Deposition of Polymer Films

Abstract

Chemical vapor deposition of polymer films eliminates the need for organic solvents and thereby offers a safer and cleaner alternative to liquid‐phase processing. This article discusses the mechanism, benefits, and capabilities associated with several types of vapor‐phase polymerization methods with a particular emphasis on initiated chemical vapor deposition (iCVD) and oxidative chemical vapor deposition (oCVD). The iCVD technique can be used to produce films that exhibit a wide range of properties such as hydrophobicity, hydrophilicity, and responsiveness to heat, pH, and light, whereas the oCVD method can be used to make conductive films. These deposition techniques allow for the controlled fabrication of high molecular weight polymer films with deposition rates as fast as several hundred nanometers per minute and can be used to modify the surfaces of three‐dimensional curved, pillared, and porous substrates since there are no solvent tension effects such as clogging or wetting.

Vapor Phase Fabrication of Hydrophilic and Hydrophobic Asymmetric Polymer Membranes

“…In this work, we present a novel technique to synthesize asymmetric membranes by the combination of both conventional and nonconventional conditions of the initiated chemical vapor deposition process (iCVD). The iCVD process is a solventless technique that has the ability to produce dense films with thicknesses ranging from tens of nanometers to several micrometers . In the conventional iCVD process, the monomer partial pressure is kept below its saturation pressure at a given substrate temperature to achieve surface adsorption of monomer .…”

Formation of Porous Polymer Coatings on Complex Substrates Using Vapor Phase Precursors

“…One potential solution is to use initiated chemical vapor deposition (iCVD), which is a solventless process that is traditionally used to create thin dense films and has been shown to be scalable with roll‐to‐roll processing . In dense film formation, monomer and initiator are fed into the reactor at partial pressures under their saturation pressures, typically at substrate temperatures between 20 and 50 °C . Polymerization occurs when gaseous monomer adsorbed to the surface of the substrate reacts with free radicals produced from the thermal decomposition of the initiator.…”

Effect of transition metal salts on the initiated chemical vapor deposition of polymer thin films

“…1,2 For these reasons, vapor phase polymerization processes have been widely used to conformally coat a variety of geometrically complex and chemically sensitive substrates. For example, silica microtoroids were coated with poly(N-isopropyl acrylamide) for humidity detection, 3 implantable neural probes were coated with Parylene to enhance tissue integration, 4 and paper-based microfluidic devices were coated with pH-responsive coatings for the separation of small molecules.…”