Tailoring the Chain Packing in Ultrathin Polyelectrolyte Films Formed by Sequential Adsorption: Nanoscale Probing by Positron Annihilation Spectroscopy
John F Quinn, Steven J Pas, Anthony Quinn, Heng Pho Yap, Ryoichi Suzuki, Filip Tuomisto, Bijan S Shekibi, James I Mardel, Anita J Hill, Frank Caruso
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | AMER CHEMICAL SOC | Published : 2012
Depth profiling experiments by positron annihilation spectroscopy have been used to investigate the free volume element size and concentration in films assembled using the layer-by-layer (LbL) adsorption method. Films prepared from strong polyelectrolytes, weak polyelectrolytes, hydrogen-bonding polymers, and blended polyelectrolyte multilayers have different chain packing that is reflected in the free volume characteristics. The influence of various parameters on free volume, such as number of bilayers, salt concentration, solution pH, and molecular weight, has been systematically studied. The free volume cavity diameters vary from 4 to 6 Å, and the free volume concentrations vary from (1.1..View full abstract
This work was supported by the Australian Research Council through the Discovery Project (F.C.) scheme. Additionally, support through the ARC Federation Fellowship scheme (RC.), the ARC Australian Postdoctoral Fellowship scheme (S.J.P., J.F.Q,), and the CSIRO Science Leader Scheme (B.S., JIM., A.J.H.) is also gratefully acknowledged. The access to the major research facilities program is supported by the Commonwealth of Australia under the International Science Linkages program. Prof. Tim Bastow is thanked for assistance with data collection. Dr. Jiwei Cui and Joseph J. Richardson (The University of Melbourne) are thanked for assistance with the SEM measurements.