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Surface Grafting Polyphosphoesters on Cellulose Nanocrystals To Improve the Emulsification Efficacy
journal contribution
posted on 2019-08-20, 16:03 authored by Suphatra Hiranphinyophat, Yuta Asaumi, Syuji Fujii, Yasuhiko IwasakiParticle-stabilized
emulsion systems have been developed to address
the problematic properties of conventional surfactants. However, the
nature and properties of the fine particles used in such systems remain
a critical issue for stability enhancement. Herein, we describe a
thermoswitchable oil-in-water (O/W) particle-stabilized emulsion that
exhibits improved stability due to the addition of cellulose nanocrystals
(CNCs) modified with poly[2-isopropoxy-2-oxo-1,3,2-dioxaphospholane]
(PIPP), which exhibits relatively good biocompatibility and biodegradability.
Various parameters, such as surface activity, concentration of particles,
polarity of solvents, and temperatures, on the formation of emulsions
with CNCs grafted with PIPP (CNC-g-PIPP) were investigated.
Results showed that the surface activity of CNC-g-PIPP was significantly improved compared with the unmodified material.
Heptane-in-water particle-stabilized emulsions with CNC-g-PIPP were stably formed, and the effect of temperature on the stability
of the emulsions was characterized. CNC-g-PIPP exhibited
function as an effective particulate emulsifier at 4 °C because
of the strong adsorption at the oil–water interface. However,
the emulsions rapidly disintegrated at 45 °C, which is above
the low critical solution temperature of PIPP on CNC, as the hydrophobized
CNC-g-PIPP desorbed from the oil–water interface.
Based on these findings, a thermally induced reversible emulsification/demulsification
was presented. The resulting switchable particle-stabilized emulsion
based on CNC-g-PIPP shows promise for the ability
to control the stability of an emulsion in response to temperature,
which is attractive for use in biological applications.