1000.
The self-assembly of amphiphilic cholesteryl-bearing carboxymethylcellulose derivatives (CCMCs) from individual molecules
to self-aggregates, in addition to their rheological
behaviour in aqueous solution were investigated. The conformations of
the individual CCMC individual molecules and self-aggregates, and the microstructures of CCMC self-aggregates were characterized
using the static and dynamic light scattering analyses, and the steady fluorescence technology. The results showed that the
individual CCMC chains became compact, and aqueous NaCl solution changed from an approximate
θ solvent to a bad one when the number of hydrophobic cholesteryl groups increased. The CCMC self-aggregates exhibited as compact
spheres. The microstructural characterization indicated that one CCMC self-aggregate consisted of multiple individual CCMC
molecules and hydrophobic microdomains, and multiple cholesteryl groups self-associated into one hydrophobic microdomain.
The atomic force microscopy images of CCMC self-aggregates in phase mode showed that the multiple interior hydrophobic phase
separation regions were surrounded by hydrophilic polysaccharide chains, providing an evidence for multiple hydrophobic microdomains
in one self-aggregate. The rheological analysis proved that the CCMC self-aggregates were a microgel, in which the associations
of cholesteryl groups provided multiple cross-linking points in the polymer network. The microgel solutions displayed a unique
thixotropy and a shear thinning
behaviour.
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