Methods of loading and releasing low molecular weight cationic molecules in weak polyelectrolyte multilayer films

Aram Chung, M. F. Rubner

Research output: Contribution to journalArticle

274 Citations (Scopus)

Abstract

This work studied the loading capabilities and release behavior of poly(acrylic acid) (PAA) and poly-(allylamine hydrochloride) (PAH) multilayer films, using methylene blue dye (MB) as an indicator. PAA/PAH multilayers assembled at pH = 2.5/2.5 loaded MB throughout the multilayers due to available binding sites and a permeable structure. The amount of MB loaded increased linearly with increasing film thickness. Use of buffered MB solutions enabled faster and more uniform MB loading into the multilayers, because ions within the MB solution caused further swelling of the multilayer film. Release studies demonstrated a pH-sensitive release mechanism, where lower pH environments increased the release rate. Buffered environments also increased the release rate of MB from the multilayer films. By assembling capping layers of PAA/PAH at pH 6.5/6.5 on top of 2.5/2.5 PAA/PAH multilayers, the diffusion of MB through the multilayers was better controlled under nonbuffered conditions. Under buffered conditions, however, the permeability of the 6.5/6.5 PAA/PAH capping layers increased due to swelling, and MB diffusion was not hindered. Further work needs to be done to slow release of MB under buffered conditions. The controlled loading capabilities and pH-sensitive release behavior of weak polyelectrolyte multilayer films demonstrated here may be useful toward drug delivery applications.

Original languageEnglish
Pages (from-to)1176-1183
Number of pages8
JournalLangmuir
Volume18
Issue number4
DOIs
Publication statusPublished - 2002 Feb 19
Externally publishedYes

Fingerprint

Methylene Blue
Multilayer films
methylene blue
releasing
low molecular weights
Polyelectrolytes
Coloring Agents
Dyes
Molecular Weight
dyes
Molecular weight
Molecules
hydrochlorides
molecules
Multilayers
carbopol 940
swelling
Swelling
acrylic acid
Binding sites

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Methods of loading and releasing low molecular weight cationic molecules in weak polyelectrolyte multilayer films. / Chung, Aram; Rubner, M. F.

In: Langmuir, Vol. 18, No. 4, 19.02.2002, p. 1176-1183.

Research output: Contribution to journalArticle

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