Growth kinetics of plasma-polymerized films

Recently, considerable interest has been shown in the fabrication of polymer materials for particular applications such as flexible electronic devices1,2,3. Accordingly, to prepare the polymer thin films, some attempts have been made using various deposition methods such as plasma sputtering, pulsed laser deposition, molecular beam epitaxy, and chemical vapor deposition4. A key issue for the preparation of polymer thin films is the need to understand the growth kinetics of the film. The growth kinetics of metal or oxide thin films prepared by physical or chemical deposition methods are well known, with many studies carried out5,6. In the polymer thin films, Michelmore et al. reported the early stage of the growth kinetics as island-like initial growth with subsequent continuous film growth7. However, a lack of information on the growth kinetics of polymer thin films still remains an issue. Consequently, the wide application of the preparation of polymer thin films is still restricted. In particular, even though plasma-based deposition methods such as plasma-enhanced chemical vapor deposition, among the various deposition methods, have potential for further applications of the preparation of polymer thin films, growth kinetics has thus far not been clearly understood. Plasma polymerization is a “dry” process since no solvents are used and does not require purification steps. In addition, films grown by plasma-based deposition methods can be deposited on any type of substrate, regardless of shape4. Thus, further application of the plasma-based deposition methods necessitates the understanding of growth kinetics in plasma-polymerized thin films. Previous reports already show that atomic force microscopy (AFM) is an excellent tool for exploring growth kinetics of film deposition as well as phase transition, etc5,8,9,10,11. Here, we demonstrate the growth kinetics of plasma-polymerized thin films using AFM.