ABSTRACT
The composition of the coating can be modified to some extent by attaching substituents to the ring carbons of the DPX molecule. Although many versions of parylene process feedstock DPX are known, those that are commercially available at this time include DPXN, the base hydrocarbon; DPXC, with an average of one chlorine atom per aromatic ring; and DPXD, averaging two chlorine atoms per aromatic ring. The coatings prepared starting with these dimers are called Parylene N, Parylene C, and Parylene
D, respectively. Substituents reduce the volatility of the monomer, causing the processing characteristics of the modified versions to be somewhat different.
