Biomedical Engineering Reference
In-Depth Information
Chapter 10
T
HE
E
FFECT OF
N
ANO
-
AND
M
ICROPARTICLES ON
P
HASE
S
EPARATION AND THE
S
TRUCTURE OF
S
EMIDILUTE
B
IOPOLYMER
M
IXTURES
Y. A. Antonov
*
and P. Moldenaers
N.M. Emanuel Institute of Biochemical Physics,
Russian Academy of Sciences, Moscow, Russia
K.U. Leuven, Department of Chemical Engineering, Leuven, Belgium
A
BSTRACT
We examine the issue of whether of low-volume fractions of nano- and
microparticles can lead to phase separation in semidilute biopolymer mixture. To this
end, we determine the phase diagrams and ESEM images of aqueous semidilute and
weakly structured sodium caseinate-sodium alginate-dextran sulfate (SC-SA-DS) system
in the presence of several the ultra clean charged micro particles with a diameter less,
higher, and comparable with the size of the system network holes (2-3 um).We
demonstrate that the last 3 um particles (both negatively and positively charged) help to
enhance phase separation, and increase the viscoelastic properties of the emulsion,
whereas the larger particles affect oppositely, and nanoparticles (210 nm and 910 nm in
diameter) do not affect appreciably the phase separation and rheology. Experimental
observations suggest that the dominant mechanism responsible for decrease
thermodynamic compatibility in such system is perfect build 3 um particles into the holes
(2-3 um in diameter) of the weak network of SC enriched phase and reinforcement of this
network. Decrease in compatibility and increase in viscoelastisity are more pronounced
by use highly charged hydrophobic carboxylate modified sulfonate latex (CLM-Sfn) and
sulfate latex, and, in less degree, by use of aliphatic amino latex, and hydrophilic CLM
latex.
Keywords:
Biopolymer emulsion, demixing, particles, structure formation
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