Molecular dynamics simulations of the growth of poly(chloro-para-xylylene) films

Abstract

Parylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results are consistent with a polymer film scaling growth mechanism and contribute to the description of the dynamic growth of the parylene C polymer.

Fig. 1

Simulated systems after 2 ns molecular dynamics. Water surface contained about 8800 water molecules and 110x110x42 Å approximate Q3 size. The distance between water surface and the parylene molecule was set to about 5 and 15 Å in a first and second layer, respectively

Fig. 2

The angle between the surface created by the aromatic ring of every unit and the water surface. (a) Definition of the angle. (b) Top: the average angle. Bottom: the angle distribution. The angle population was divided for three ranges 0–30 – red, 30–60 – green and 60–90 – blue and plotted as a percentage of distribution

Fig. 3

Dihedral angle between the aromatic rings of two vicinal units. (a) Definition of the angle. (b) Top: the average angle. Bottom: the angle distribution. The angle population was divided for three ranges 0–30 – red, 30–90 – green, 90–150 – blue and 150– 180 – orange and plotted as a percentage of distribution