Pulsed Radio Frequency Plasma Polymerization of Allyl Alcohol:  Controlled Deposition of Surface Hydroxyl Groups

Abstract

The utility of employing a variable duty cycle pulsed plasma polymerization technique to control film chemistry during plasma depositions is examined using allyl alcohol as monomer gas. Large scale progressive variations in film composition are observed with sequential changes in the plasma duty cycles employed, all other plasma variables being held constant. In particular, the −OH functionality of the monomer is increasingly retained in the plasma generated thin films as the radio frequency duty cycle is lowered. Fourier transform infrared and X-ray photoelectron spectroscopic analyses of the films obtained reveal that excellent film chemistry control is achieved during plasma polymerization of this monomer. The surface density controllability of functional groups, coupled with a gradient layering technique described herein to improve film adhesion to substrate surfaces, provides ideal opportunities for molecular tailoring of surfaces via subsequent derivatization reactions.

Species and Density of Implant Surface Chemistry Affect the Extent of Foreign Body Reactions

“…The binding energy of the C(1s) component representing carbon atoms not bonded to oxygen atoms was adjusted to a value of 284.6 eV. 47 A Bi-Rad, Model FTS-40, operated at 8 cm −1 resolution and transmission mode, was used for the FT-IR characterizations. Wettability of the surfaces was measured using a static angle Rame-Hart sessile drop goniometer, as described in our previous work.…”

On the importance of ions and ion-molecule reactions to plasma-surface interface reactions

“…Another approach to limiting the depositing film's exposure to charged species is to use pulsed plasmas [50] which have been shown to reduce trapped radicals in the depositing films, lower deposition surface temperatures, and decrease ion and UV flux to the surface. Consequently, greater control over the resulting film chemistry is achieved, with higher retention of the monomer functionalities [47].…”

Fibrinogen adsorption and host tissue responses to plasma functionalized surfaces

“…To this end, using pulsed radio frequency glow discharge (RFGD), we have generated surfaces bearing different functional groups with varying hydrophobicities. The procedure involves a flowing gas system in which an ionized gas plasma is repeatedly generated (with on and off cycles) to provide, via polymerization of an appropriate monomer, [22][23][24] thin film coatings with different functional groups. In the present work, pulsed RFGD was used to coat polyethylene terephthalate disks with different surface functionalities, including −OH (from allyl alcohol), −NH 2 (from allylamine), −CF 3 (from C 9 F 18 perfluorohexene), and siloxyl groups [from hexamethyldisiloxane (HMDSO)].…”