Document Detail


Double Emulsions and Colloidosomes-in-Colloidosomes Using Silica-based Pickering Emulsifiers.
MedLine Citation:
PMID:  24559174     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Poly(ethylene imine) (PEI) has been adsorbed onto the surface of fumed silica particles at pH 10 in order to produce an effective 'hybrid' Pickering emulsifier. Systematically increasing the PEI/silica mass ratio modifies the particle surface sufficiently to stabilize oil-in-water (o/w) Pickering emulsions using a fixed silica concentration of 1.0 wt. % in conjunction with an aldehyde-rich multi-component oil via homogenization at 12 000 rpm for 2 min at 20 °C. Further increasing the PEI/silica mass ratio leads to phase inversion, producing water-in-oil (w/o) Pickering emulsions. Thus this system allows formation of stable water-in-oil-in-water (w/o/w) double emulsions using two batches of hydrophilic and hydrophobic silica particles that differ only in their PEI/silica mass ratios prior to homogenization. Stable w/o/w double emulsions can be prepared with oil volume fractions ranging from 5 to 42 %. Moreover, controlling the volume fraction of the w/o Pickering emulsion homogenized in the presence of an aqueous dispersion of the hydrophilic PEI-silica particles allows the mean diameter of the resulting double emulsion droplets to be conveniently controlled between 20 and 160 μm. Fluorescence microscopy studies confirm that, by controlling the mean diameter of the larger double emulsion droplets, the number of smaller droplets encapsulated within each larger droplet can be varied so as to allow encapsulation of either single or multiple droplets. Although these double emulsions do not require cross-linking at either interface to withstand an alcohol challenge, epoxy-amine cross-linking between the physically-adsorbed PEI chains and either an oil-soluble or a water-soluble bisepoxy-based polymeric cross-linker can be achieved to produce novel colloidosomes-in-colloidosomes, which may offer payload retention benefits over conventional colloidosomes.
Authors:
Mark Williams; Steven P Armes; Pierre Verstraete; Johan Smets
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-2-21
Journal Detail:
Title:  Langmuir : the ACS journal of surfaces and colloids     Volume:  -     ISSN:  1520-5827     ISO Abbreviation:  Langmuir     Publication Date:  2014 Feb 
Date Detail:
Created Date:  2014-2-24     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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