Dry polymerization of functional thin films and multilayers by chemical vapor deposition

Responsive polymers with electronic and photonic properties have recently gained a widespread interest because of their versatility and cheapness. Chemical vapor deposition (CVD) offers a method to combine the large portfolio of conventional organic polymerization with the advantages of easy thin film processing, uniformity and scalability. CVD polymerization takes place in a mild vacuum environment, the substrate is kept near room temperature and in the complete absence of solvent. This allows to deposit polymers on unconventional delicate and flexible substrates, such as paper or plastic, with control over thickness on large areas. High reflectance distributed Bragg reflectors are based on multilayer structures whose growth can be facilitated by the absence of solvent, hence without risk of swelling or dissolving the underlying material. The conformal coverage of three-dimensional feature is also a unique characteristic of CVD polymers. In this chapter, fundamental background together with successful applications of CVD polymers will be reviewed. New techniques, as initiated CVD and oxidative CVD, will be introduced and it will be emphasized how they allow to obtain polymers with high chemical specificity (i.e., large retention of chemical functionality) at elevated speed. The accent will be on the applications where all-dry-processing is critical, such as deposition of insoluble polymers (e.g., highly cross-linked) for reactive and responsive surfaces, molecular crystals of fluoropolymers, conjugated polymers, composite and multilayer structures.