Surface Morphology in the Early Stages of Plasma Polymer Film Growth from Amine‐Containing Monomers

Abstract

The manner by which plasma polymers grow in the very first stages of deposition is a topic which has been almost overlooked. We show using atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS) that in the early stages of plasma deposition there are significant differences in the way plasma polymers grow from two amine‐containing compounds onto silicon wafers. By AFM it is shown that films grown from n‐heptylamine (HA) initially show ‘island‐like’ growth before a continuous smooth film is formed. In contrast, films from allylamine grow smoothly from the very earliest stages. XPS data show substantial differences of plasma polymer chemistry in close proximity to the silicon surface manifested in the formation of ${\rm NH}_{{\rm 3}}^{{\rm + }} $ and NOx species which are more abundant in films of HA. We present a possible explanation for these results based upon post‐plasma surface phenomena in the case of HA.

Hybrid core/shell microparticles and their use for understanding biological processes

“…1). Our published studies demonstrated that plasma polymer films of this thickness are continuous and pinhole free [33,39]. The choice of ACpp as an overlayer was based on previous biological in vitro studies on planar surfaces which showed that ACpp coatings significantly reduced the inflammatory response.…”

“…A key benefit of the technique is that it can be applied to any type of substrate material as the technique is practically substrate independent and no surface pre-modification is required [33][34][35][36]. In contrast, self-assembled monolayers (SAM) require specific starting materials, LBL requires charged surfaces with multiple layers, and atomic layer deposition (ALD) can produce limited surface chemistry [33]. Another advantage of using plasma polymerization is that it is pin hole free, and conformal thin films can be deposited by using a single step coating procedure [37,38].…”

Optimizing Humic Acid Removal by Modifying the Surface Chemistry of Plasma Polymerized Allylamine Coated Particles

“…Previous research has shown that ppAA films are deposited as a continuous film, rather than island formation, even for the shortest polymerization times. [26,43] If ppAA films were initially deposited as islands, then the increase in the number of positively charged groups would be attributed to the growth of these islands and eventual joining. The XPS data in Figure 9 indicates the ppAA film increases in thickness, and therefore, it is proposed that the increase in the number of positively charged groups with increasing film thickness is due to penetration of dye into the ppAA film.…”

Incorporation of Primary Amines via Plasma Technology on Biomaterials

“…Michelmore et al [66] noticed that films grown from n-heptylamine initially show "islandlike" growth before a continuous smooth film is formed. In contrast, films from allylamine grow smoothly from the very earliest stages.…”

“…AFM can be used to study the way plasma polymers grow: AFM images have been used to show the surface morphology of the deposited films while varying the treatment time [66]. AFM analysis is useful, not only in a qualitative way but also for quantitative determinations, since it allows a 3D representation of the treated surface and quantifies the effects of the plasma-etching mechanism by calculation of the surface roughness (root-mean-squared roughness, R rms ) [44].…”