Enhanced Dewatering of Polyelectrolyte Nanocomposites by Hydrophobic Polyelectrolytes

We demonstrate that increasing the hydrophobic environment around the charge center of a polyelectrolyte (PE) not only decreases the water content of an adsorbed PE layer but can even dewater up to ∼50% of an initially hydrated substrate. The results of this work are expected to yield new stratagies...

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Bibliographic Details
Published in:Langmuir 2012-07, Vol.28 (30), p.11086-11094
Main Authors: Kittle, Joshua D, Wondraczek, Holger, Wang, Chao, Jiang, Feng, Roman, Maren, Heinze, Thomas, Esker, Alan R
Format: Article
Language:English
Subjects:
Chemistry
Exact sciences and technology
General and physical chemistry
Hydrophobic and Hydrophilic Interactions
Nanocomposites - chemistry
Polymers - chemistry
Surface physical chemistry
Surface Plasmon Resonance
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Summary:We demonstrate that increasing the hydrophobic environment around the charge center of a polyelectrolyte (PE) not only decreases the water content of an adsorbed PE layer but can even dewater up to ∼50% of an initially hydrated substrate. The results of this work are expected to yield new stratagies to dewater PE systems and have potential applications in mineral recovery, paper manufacturing, and biomedical materials. Adsorption of a series of cationically derivatized dextran polyelectrolytes onto sulfated nanocrystalline cellulose (SNC) has been studied using quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR). Synthesized samples of (N,N-dimethylamino)ethyldextran (DMAE-Dex), (N,N-diethylamino)ethyldextran (DEAE-Dex), and (N,N-diisopropylamino)ethyldextran (DIAE-Dex) had degrees of substitution (DS) ranging from 0.05 to 0.82. DMAE-Dex, DEAE-Dex, and DIAE-Dex all showed decreasing adsorption onto SNC and decreasing water content of the adsorbed film with increasing DS. Additionally, DEAE-Dex and DIAE-Dex films adsorbed onto SNC contained less water than DMAE-Dex films with the same DS. Interestingly, QCM-D results for high DS DIAE-Dex adsorbed onto SNC revealed mass loss, whereas SPR results clearly showed DIAE-Dex adsorbed. These observations were consistent with dehydration of the SNC substrate. This study indicates that the water content of the substrate could be tailored by controlling the DS and hydrophobic character of the adsorbed polyelectrolytes.
ISSN:0743-7463
1520-5827
DOI:10.1021/la3016996