Document Detail


Adsorption of PEO-PPO-PEO Triblock Copolymers with End-Capped Cationic Chains of Poly(2-dimethylaminoethyl methacrylate).
MedLine Citation:
PMID:  21721578     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
We study the adsorption of a symmetric triblock copolymer of ethylene oxide, EO, and propylene oxide, PO, end-capped with quarternized poly(2-dimethylaminoethyl methacrylate), DMAEMA (DMAEMA24-EO132PO50EO132-DMAEMA24). Light scattering and tensiometry are used to measure the relative size of the associated structures and surface excess at the air-liquid interface. The adsorbed amount, the amount of coupled water and the viscoelasticity of the adsorbed polymer layer are measured on hydrophobic and hydrophilic surfaces (polypropylene, cellulose and silica) by using quartz crystal microgravimetry (QCM) and surface plasmon resonance (SPR) at different ionic strengths and temperatures. The results of the experiments are compared with those obtained after adsorption of the uncharged precursor copolymer, without the cationic end caps (EO132PO50EO132). DMAEMA24-EO132PO50EO132-DMAEMA24 possesses higher affinity with the negatively-charged silica and cellulose surfaces while the uncharged copolymer adsorbs in a larger extent on polypropylene surfaces. In this latter case, adsorption increases with increasing solution ionic strength and temperature. Adsorption of EO132PO50EO132 on silica surfaces has little effect on the water contact angle (WCA), while adsorption of DMAEMA24-EO132PO50EO132-DMAEMA24 increases the WCA of silica to 32 degrees, indicating a large density of exposed PPO blocks upon adsorption. After adsorption of EO132PO50EO132 and DMAEMA24-EO132PO50EO132-DMAEMA24 on PP the WCA is reduced by ca. 14 and 28 degrees, respectively due to the exposed hydrophilic EO and highly water soluble DMAEMA segments on the surfaces. The extent of surface coverage at saturation at the polypropylene/liquid interfaces (ca. 31 and 40 nm2/molecule obtained by QCM and SPR, respectively) is much lower, as expected, when compared with results obtained at the air/liquid interface were a tighter packing is observed. The % of water coupled to the adsorbed cationic polymer decreases with solution ionic strength. Overall, these observations are ascribed to the effects of electrostatic screening, polymer hydrodynamic size and solvency.
Authors:
Xiaomeng Liu; Arja-Helena Vesterinen; Jan Genzer; Jukka V Seppälä; Orlando Jose Rojas
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-7-2
Journal Detail:
Title:  Langmuir : the ACS journal of surfaces and colloids     Volume:  -     ISSN:  1520-5827     ISO Abbreviation:  -     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-7-4     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882736     Medline TA:  Langmuir     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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