AVS 46th International Symposium
    Biomaterial Interfaces Group Wednesday Sessions
       Session BI-WeP

Paper BI-WeP13
Thermally Responsive Ultrathin Coatings by RF-Plasma Deposition

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: Y.V. Pan, University of Washington
Authors: Y.V. Pan, University of Washington
R.A. Wesley, University of Washington
R. Luginbuhl, University of Washington
R.M. Overney, University of Washington
D.D. Denton, University of Washington
B.D. Ratner, University of Washington
Correspondent: Click to Email
Poly(n-isopropyl acrylamide) (pNIPAM) shows a lower critical solution temperature (LCST) of 31@super o@C in aqueous environment. At temperatures lower than the LCST, the polymer chains are well hydrated and fully extended. The polymer chains dehydrate and take on a more compact configuration above the LCST. This interesting phase transition behavior has been observed here with pNIPAM chains grafted onto solid surfaces by plasma deposition. In this presentation, thermally responsive coatings are prepared f rom glow discharges of NIPAM vapor. The synthesis and spectroscopic characterization (XPS, SIMS) of plasma polymerized NIPAM (ppNIPAM) will be presented. The ppNIPAM coatings obtained showed a remarkable retention of the monomer structure, and a phase tr a nsition at 31@super o@C in both water and air. The phase transition was measured by a novel AFM method. The water phase transition was surprising because of the expectation that the plasma environment would destroy the specific NIPAM structure associat ed with t he thermal responsiveness. However, the transition in air was even more unexpected and suggests that adsorbed water on the AFM tip and at the polymer surface is sufficient to produce the phase change, even when the bulk of the polymer is unhydrated. Plasma polymerization of NIPAM represents a one-step method to fabricate thermally responsive coatings without specially prepared substrates and functionalized polymers.