TY  - JOUR
A1  - Dodoo, Samuel
A1  - Balzer, Bizan N.
A1  - Hugel, Thorsten
A1  - Laschewsky, André
A1  - von Klitzing, Regine
T1  - Effect of ionic strength and layer number on swelling of polyelectrolyte multilayers in water vapour
JF  - Soft materials
N2  - The swelling behavior of polyelectrolyte multilayers (PEMs) of poly(sodium-4 styrene sulfonate) (PSS) and poly(diallyl dimethyl ammonium chloride) (PDADMAC) prepared from aqueous solution of 0.1 M and 0.5 M NaCl are investigated by ellipsometry and Atomic Force Microscopy (AFM). From 1 double-layer up to 4 double-layers of 0.1 M NaCl, the amount of swelling water in the PEMs decreases with increasing number of adsorbed double layers due to an increase in polyelectrolyte density as a result of the attraction between the positively charged outermost PDADMAC layer and the Si substrate. From 6 double layers to 30 double layers, the attraction is reduced due to a much larger distance between substrate and outermost layer leading to a much lower polyelectrolyte density and higher swelling water. In PEMs prepared from aqueous solution of 0.5 M NaCl, the amount of water constantly increases which is related to a monotonically decreasing polyelectrolyte density with increasing number of polyelectrolyte layers. Studies of the surface topology also indicate a transition from a more substrate affected interphase behavior to a continuum properties of the polyelectrolyte multilayers. The threshold for the transition from interphase to continuum behavior depends on the preparation conditions of the PEM.
KW  - Continuum properties
KW  - Interphase behavior
KW  - Ionic strength
KW  - Multilayers
KW  - Polyelectrolytes
KW  - Substrate effect
KW  - Swelling behavior
KW  - Threshold
KW  - Water vapor
Y1  - 2013
U6  - https://doi.org/10.1080/1539445X.2011.607203
SN  - 1539-445X
VL  - 11
IS  - 2
SP  - 157
EP  - 164
PB  - Taylor & Francis Group
CY  - Philadelphia
ER  -