Linked Life Data

16852135

Source:http://linkedlifedata.com/resource/pubmed/id/16852135

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
2006-7-20
pubmed:abstractText
Well-defined amphiphilic cubic silsesquioxane-poly(ethylene oxide) (CSSQ-PEO) was prepared from octakis (dimethylsiloxy)octasilsesquioxane (Q8M8(H)) and allyl-PEO through a hydrosilylation reaction. The structure of CSSQ-PEO was characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). The amphiphilic properties and aggregation process of CSSQ-PEO in aqueous solution were investigated by fluorescence, dynamic and static light scattering (DLS and SLS), and transmission electron microscopy (TEM). The critical aggregation concentration (CAC) determined by fluorescence measurements was found to be 0.28 mg/mL. Combinations of DLS, SLS, and TEM studies showed the existence of core-corona micelle with hydrophobic CSSQ as the core and hydrophilic PEO as the corona in aqueous solution. The observation of two size distribution peaks from DLS measurements revealed the coexistence of small amounts of unassociated unimolecular micelles (approximately 10% of the scattered intensity) together with micellar aggregates when the CSSQ-PEO concentration was < or = 2 mg/mL. The hydrodynamic radii (R(h)) of unassociated unimolecular micelle and micellar aggregates were found to be 26 and 79 nm, respectively. A large R(g)/R(h) ratio (1.46) and the extremely small value of average chain density (4 x 10(-4) g/cm3) indicate the small hydrophobic CSSQ core was surrounded by the extended PEO coronae. The aggregation number (N(agg)) of CSSQ-PEO in aqueous solution was found to be 38 +/- 2 from SLS and 31-40 from TEM, respectively. The long PEO segments act as a spacer between the spherical aggregates, which facilitate the formation of a network-like structure at high concentration.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-6106
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
109
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9455-62
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:16852135-Chemistry, Physical, pubmed-meshheading:16852135-Chromatography, Gel, pubmed-meshheading:16852135-Indicators and Reagents, pubmed-meshheading:16852135-Light, pubmed-meshheading:16852135-Magnetic Resonance Spectroscopy, pubmed-meshheading:16852135-Microscopy, Electron, Transmission, pubmed-meshheading:16852135-Organosilicon Compounds, pubmed-meshheading:16852135-Physicochemical Phenomena, pubmed-meshheading:16852135-Polyethylene Glycols, pubmed-meshheading:16852135-Quaternary Ammonium Compounds, pubmed-meshheading:16852135-Refractometry, pubmed-meshheading:16852135-Scattering, Radiation, pubmed-meshheading:16852135-Solutions, pubmed-meshheading:16852135-Spectrometry, Fluorescence, pubmed-meshheading:16852135-Spectroscopy, Fourier Transform Infrared, pubmed-meshheading:16852135-Water
pubmed:year
2005
pubmed:articleTitle
Core-corona structure of cubic silsesquioxane-poly(ethylene oxide) in aqueous solution: fluorescence, light scattering, and TEM studies.
pubmed:affiliation
Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Republic of Singapore.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't