Fabrication of large scale polymeric thin films by close batch initiated chemi̇cal vapor deposition method

In this study, it is shown that poly (ethylhexyl acrylate) and poly (ethylhexyl acrylate-co-ethylene glycol dimethacrylate) thin films were successfully synthesized in large scale batch initiator chemical vapor deposition (iCVD) system. The batch iCVD system was used in the production of thin films because the problems arose when adjusting flow rate of precursor. Horizontal cylindrical stainless steel vacuum tank, which is frequently used in industrial vacuum applications, was used as iCVD reactor. In the synthesis of poly (ethylhexyl acrylate), the effects of substrate temperature, precursor ratio and pressure on the deposition rate were investigated. In a single run, deposition rate of 315 nm/min was obtained at 600 mtorr reactor pressure. At 400 mtorr reactor pressure, a decrease in deposition rate was observed. But the uniformity of thin films have ıncreased. Thicker films can be obtained without the need for abundant monomer consumption by making depositions at successive cycles. The yield percentage of films produced with the batch system at 400 mtorr was found to be 3.5. This value is 35 fold bigger compared to the yield percentage of films sythesized in the classical iCVD system. The parameters obtained in the synthesis of PEHA were used for the synthesis of Poly (EHA-co-EGDMA) thin film. The effect of partial pressure on the deposition rate and chemical properties in copolymer synthesis was investigated. Synthesized copolymers showed better chemical and thermally stable properties than homopolymer. The chemical structure of films using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometry (XPS), and film thickness and homogeneity with optical spectrometry, and film properties were determined by contact angle analysis.