AVS 51st International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI-FrM

Paper BI-FrM2
Thermally Responsive Surfaces Formed by Plasma Polymerisation of N-Isopropyl Acrylamide

Friday, November 19, 2004, 8:40 am, Room 210D

Session: "Active" - Dynamic Biointerfaces
Presenter: N.A. Bullett, University of Sheffield, UK
Authors: N.A. Bullett, University of Sheffield, UK
R.A. Talib, University of Sheffield, UK
S.L. McArthur, University of Sheffield, UK
R.D. Short, University of Sheffield, UK
A.G. Shard, University of Sheffield, UK
Correspondent: Click to Email
Temperature responsive surface coatings show great potential for a number of novel applications, such as 'smart' cell culture substrates for the control of cell attachment and detachment. Surface grafted N-isopropyl acrylamide (NIPAAm) has been shown to be suitable for this purpose, and the possibility of producing these coatings by deposition from plasma has been recently demonstrated by Pan et al.@footnote 1@ We find that, although it is possible to produce surfaces that demonstrate a temperature-dependent transition (as determined by contact angle goniometry and ellipsometry), there is a significant risk of delamination or solubilisation of the plasma polymers when they are in contact with water. In this work we demonstrate the importance of substrate temperature and discharge power on the properties of plasma polymerized NIPAAm. X-ray photoelectron spectroscopy (XPS) analyses were used to examine the composition of the deposited films, demonstrating that the high power deposits contain less characteristic functional groups (notably amides), indicating greater fragmentation of the monomer, and a high degree of cross-linking, whilst the low power deposit closely resembles conventionally polymerised NIPAAm. However, the very low power plasma polymers were shown, by XPS analysis and ellipsometry, to be unstable to rinsing with distilled water. The effect of substrate temperature during deposition was also investigated. It was found that higher substrate temperatures produced a more stable film at lower plasma powers. Useful films are therefore only produced within a narrow parameter space. The effect of using pulsed discharges and co-monomers was also investigated. We demonstrate that these plasma polymers can be patterned and used for cellular co-culture. @FootnoteText@ @footnote 1@ Pan YV, Wesley RA, Luginbuhl R, Denton DD, Ratner BD; Biomacromolecules 2001, 2, 32-36.