Direct visualization of the real time swelling and collapse of a poly(methacrylic acid) brush using atomic force microscopy

Condensed Matter journal club

Direct visualization of the real time swelling and collapse of a poly(methacrylic acid) brush using atomic force microscopy

  • Event time: 11:30am
  • Event date: 30th January 2009
  • Speaker: Alastair Mailer (Formerly School of Physics & Astronomy, University of Edinburgh)
  • Location: Room 2511,

Event details

Abstract

The reversible height change dynamics of a poly(methacrylic acid) brush, a weak polyelectrolyte in response to pH changes, were observed using atomic force microscopy. The brush thickness could be repeatably and reversibly switched between 40 nm at pH 3 and 120 nm at pH 10.5. The swelling and collapse transitions took 6 s in the AFM measurements, but high resolution force spectroscopy measurements showed that the collapse can be made to happen in less than a second. We conclude that the response time of these switches is limited in practise by the physical time taken to exchange solvents and by the intrinsic slow dynamics in the brush.
Soft Mat. 5 296-299 (2009)

Authors

A.J. Parnell, S.J. Martin, R.A.L. Jones, C. Vasilev, C. J. Crook and A.J. Ryan