Controlled Release from
Model Blend Multilayer Films
Containing Mixtures of Strong and Weak Polyelectrolytes
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Abstract
We have designed the controlled release platforms based
on polyelectrolyte
(PE) blend multilayer films to investigate the release mode and kinetics
at the nanoscale level. The model blend multilayer films are composed
of positively charged layers with weak polyelectrolytes (PEs) (linear
poly(ethylenimine), LPEI) and negatively charged blend layers with
mixtures of strong (poly(sodium 4-styrenesulfonic acid), PSS) and
weak (poly(methacrylic acid), PMAA) PEs. The blend multilayer films
([LPEI/PSS:PMAA]<sub><i>n</i></sub>) with well-defined internal
structure were prepared by the spin-assisted layer-by-layer (LbL)
deposition method. Release properties of the multilayer films were
systematically studied as a function of blend ratio by neutron reflectivity
(NR), ellipsometer, AFM, FT-IR spectroscopy, and quartz crystal microbalance
with dissipation (QCM-D). Since PSS strong PEs serve as robust skeletons
within the multilayer films independent of external pH variation,
the burst disruption of pure weak PE multilayer films was dramatically
suppressed, and the release kinetics could be accurately controlled
by simply changing the PSS content within the blend films. These release
properties of blend multilayer films form the basis for designing
the controlled release of target active materials from surfaces