TY - JOUR
T1 - A new approach to improved stability and controlled release in double emulsions, by the use of graft-comb polymeric amphiphiles
AU - Garti, N.
PY - 1998
Y1 - 1998
N2 - Double emulsions are emulsion-within-emulsion systems with promising applications. Attempts have been made to find new amphiphiles to improve their thermodynamic stability and to control the release of active matter or markers from double emulsions. The present review summarizes our efforts to study the mechanisms of stabilization and release of water-soluble markers from W/OAV double emulsions, and our achievements in designing an ultimate synthetic graft-comb copolymeric amphiphile for the internal water-oil interface (the W/O emulsion) as well as for the external oil-water interface (the OAV emulsion). The amphiphilic polymers allow formation of small multicompartment emulsion droplets of W/OAV that are shear (homogenization) and mechanically (centrifugation) resistant. The interface is covered with thick emulsifier layers that impart long-term stability. Addition of controlled amounts of monomeric emulsifiers (Spans) will form reverse micelles in the oil phase, which are capable of transporting the markers via a "diffusion-controlled mechanism" from the inner to the outer interface. The tailor-made polymers are an excellent solution to the two key problems that, so far, have prevented the use of double emulsions in certain industrial applications: stability and release. Agricultural formulations, based on stabilization by these polymers, have shown considerable advantages over other common techniques of encapsulating or entrapping active matter.
AB - Double emulsions are emulsion-within-emulsion systems with promising applications. Attempts have been made to find new amphiphiles to improve their thermodynamic stability and to control the release of active matter or markers from double emulsions. The present review summarizes our efforts to study the mechanisms of stabilization and release of water-soluble markers from W/OAV double emulsions, and our achievements in designing an ultimate synthetic graft-comb copolymeric amphiphile for the internal water-oil interface (the W/O emulsion) as well as for the external oil-water interface (the OAV emulsion). The amphiphilic polymers allow formation of small multicompartment emulsion droplets of W/OAV that are shear (homogenization) and mechanically (centrifugation) resistant. The interface is covered with thick emulsifier layers that impart long-term stability. Addition of controlled amounts of monomeric emulsifiers (Spans) will form reverse micelles in the oil phase, which are capable of transporting the markers via a "diffusion-controlled mechanism" from the inner to the outer interface. The tailor-made polymers are an excellent solution to the two key problems that, so far, have prevented the use of double emulsions in certain industrial applications: stability and release. Agricultural formulations, based on stabilization by these polymers, have shown considerable advantages over other common techniques of encapsulating or entrapping active matter.
UR - http://www.scopus.com/inward/record.url?scp=0032203787&partnerID=8YFLogxK
U2 - 10.1002/(sici)1521-4044(199810)49:10/11<606::aid-apol606>3.0.co;2-g
DO - 10.1002/(sici)1521-4044(199810)49:10/11<606::aid-apol606>3.0.co;2-g
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AN - SCOPUS:0032203787
SN - 0323-7648
VL - 49
SP - 606
EP - 616
JO - Acta Polymerica
JF - Acta Polymerica
IS - 10-11
ER -