Internally self-assembled particles entrapped in thermoreversible hydrogels.
The present study describes the development of thermogelling emulsions by the entrapment of internally self-assembled emulsion droplets (ISAsomes) within a thermoreversible hydrogel made of kappa-carrageenan. The droplets are emulsified mesophases of cubic or hexagonal order, or emulsified micro-emulsions. Above 60 degrees C, the system was fluid and composed of a mixture of internally nanostructured small droplets and polymer chains dispersed in water. Below 60 degrees C, a physical gel with entrapped droplets was formed. A tuning of the temperature in order to switch between the gel and solution state did not affect the particles in terms of size. The thermoreversible behavior of the loaded polymer network and the effects on the internal structure of cubosomes, hexosomes and emulsified micro-emulsions was investigated by SAXS. We showed that the phase borders may be shifted due to the presence of the kappa-carrageenan network, which alter the internal nanostructure of the droplets. This can induce a transformation from emulsified micro-emulsions to micellar cubosomes. In the hexagonal case, the lattice parameters of the hexosomes are slightly modified.
Guillot
Samuel
S
Institute of Chemistry, University of Graz, Heinrichstrasse 28, A-8010 Graz, Austria.
Tomsic
Matija
M
Sagalowicz
Laurent
L
Leser
Martin E
ME
Glatter
Otto
O
D002351:Carrageenan / Q000737:chemistry*; D004655:Emulsions; D020100:Hydrogels / Q000737:chemistry*; D008968:Molecular Conformation; D044367:Phase Transition; D013696:Temperature
D004655:Emulsions; D020100:Hydrogels; D002351:Carrageenan