Abstract
The growth of highly functionalised poly allyl alcohol films by pulsed plasma polymerisation of CH 2 {double bond, long}CHCH 2 OH on biomedical grade polyurethane has been followed by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Film thickness is observed to increase approximately linearly with plasma modification time, suggesting a layer-by-layer growth mode of poly allyl alcohol. Water contact angle measurements reveal the change in the surface free energy of wetting decreases linearly with plasma modification up to the monolayer point after which a constant limiting value of -24 mJ m -2 was attained. Films prepared at 20 W plasma power with a duty cycle of 10 μs:500 μs exhibit a high degree of hydroxyl ({single bond}OH) retention with minimal fragmentation of the monomer observed. Increasing the plasma power up to 125 W is found to improve {single bond}OH retention at the expense of ether formation generating films close to the monomer stoichiometry. Duty cycle plays an important role in controlling both film composition and thickness, with longer off times increasing {single bond}OH retention, while longer on times enhance allyl alcohol film growth.
| Original language | English |
|---|---|
| Pages (from-to) | 8203-8211 |
| Number of pages | 9 |
| Journal | Applied Surface Science |
| Volume | 252 |
| Issue number | 23 |
| DOIs | |
| Publication status | Published - 30 Sept 2006 |
| Externally published | Yes |
Funding
Financial support is gratefully acknowledged from Smith & Nephew and the EPSRC for the provision of a DTA to LMW. KW also acknowledges the Royal Society for an Equipment Grant (2004/R2).
Austrian Fields of Science 2012
- 205019 Material sciences
- 104018 Polymer chemistry
Keywords
- Allyl alcohol
- Biomaterials
- Contact angle
- Polyurethane
- Pulsed plasma polymerisation
- Thin films
- XPS