Kinetic Roughening in Polymer Film Growth by Vapor Deposition

The growth front roughness of linear poly( $p$-xylylene) films grown by vapor deposition polymerization has been investigated using atomic force microscopy. The interface width $w$ increases as a power law of film thickness $d$, $w\sim d^{\beta }$, with $\beta =0.25\mathrm{}\pm 0.03$, and the lateral correlation length $\xi$ grows as $\xi \sim d^{1/z}$, with $1/z=0.31\pm 0.02$. This novel scaling behavior is interpreted as the result of monomer bulk diffusion, and belongs to a new universality class that has not been discussed previously.