Thermophysical properties of the parylene C dimer under vacuum

Abstract Herein, we report the thermophysical properties of dichloro-[2,2]-paracyclophane (the parylene C dimer) under vacuum. The parylene C dimer is the raw material used to prepare parylene C, a thin film known for its useful dielectric and barrier properties. In order to investigate the first step in the synthesis of parylene C by chemical vapor deposition, the sublimation, evaporation, and melting behavior of the parylene C dimer was examined by simultaneous thermogravimetry/differential thermal analysis (TG–DTA) under vacuum and at atmospheric pressure. The evaporation onset temperatures, saturation vapor pressures, and the phase-transition temperatures of the parylene C dimer were quantified by TG–DTA at various pressures. The evaporation and sublimation temperature easily decreased by increasing the level of vacuum, while the melting temperature was independent of the external pressure. Our results led to the construction of a pressure–temperature phase diagram.