Formation of polymer gels, films, and particles via initiated chemical vapor deposition onto liquid substrates

The initiated chemical vapor deposition (iCVD) process is a vapor phase is a technique used to deposit functional polymer coatings typically onto solid substrates. Our group is the first to introduce low vapor pressure liquids, such as ionic liquids and silicone oils, as substrates into the iCVD process. The use of liquid substrates adds additional complexity in the form of solubility and surface tension effects. Precursors that are soluble in the liquid have the ability to absorb into the liquid as well as adsorb to the surface and create two distinct locations of polymerization. The polymerization that occurs at the surface can result in polymer films or particles depending on the surface tension interactions between the polymer and liquid. Section 1 introduces the iCVD process and provides background on past works that studied vacuum depositions with liquid substrates as well as the applications and current methods of the polymer materials made using liquid substrates: polymer-ionic liquid gels, free standing films, and nanoparticles. Section 2 investigates the polymerization that occurs within an ionic liquid layer, focusing on the difference between polymerization within the layer and at the surface, the effect of polymer accumulation within the liquid layer, and the formation of gels. Section 3 demonstrates the different polymer morphologies formed at a variety of liquid surfaces and uses these properties to develop a method of forming shaped free standing films using a two-liquid system. Section 4 studies the growth mechanism of polymer nanoparticles formed at the liquid surface, the understanding of which can be used to synthesize of nanoparticles of a controlled size and to form polymer core-shell particles.