Microrheology of novel cellulose stabilized oil-in-water emulsions

Abstract

Diffusing wave spectroscopy (DWS) is a powerful optical technique suitable to investigate turbid samples in a nondestructive and reproducible way, providing information on the static and dynamic properties of the system. This includes the relative displacement of emulsion droplets over time and changes in the viscoelastic properties. Here, novel and promising cellulose-based oil-in-water (O/W) emulsions were prepared and studied, for the first time, by DWS. Cellulose plays the role of a novel eco-friendly emulsifying agent. The hydrolysis time of cellulose was observed to affect the average size of the emulsion droplets and their stability; the longer the hydrolysis time, the more dispersed and stable the emulsions were found to be. Additionally, a good complementarity between the microrheology (DWS) and macrorheology (mechanical rheometer) data was found. Our work suggests that DWS is a highly attractive method to investigate the stability, aging and microrheology properties of cellulose-based emulsions, providing valuable insights on their microstructure. This technique is thus highly appealing for the characterization and design of novel emulsion formulations.

Candelilla wax‐based oleogels versus palm oil: evaluation of physical properties of innovative and conventional lipids using optical techniques

“…An alternative is the multi-speckle diffusing wave spectroscopy (MS-DWS) method, which is based on tracking changes in particle motion under the influence of thermal energy in real time (through dynamic light scattering). 22 The techniques used in passive optical microrheology are practically non-invasive, so the same sample can be repeatedly used for analysis. 18 During the measurement, the mean square displacement (MSD) of a particle as a function of time at different frequencies is determined, on the basis of which microrheological parameters of the sample are calculated.…”

“…Commonly used rheological test methods consist of causing material deformation, and they are limited to the macroscopic scale. An alternative is the multi‐speckle diffusing wave spectroscopy (MS‐DWS) method, which is based on tracking changes in particle motion under the influence of thermal energy in real time (through dynamic light scattering) 22 . The techniques used in passive optical microrheology are practically non‐invasive, so the same sample can be repeatedly used for analysis 18 .…”

New Insights on the Role of Urea on the Dissolution and Thermally-Induced Gelation of Cellulose in Aqueous Alkali

“…The transmission mode was used to access the microrheological properties of the samples. DWS is a powerful optical technique suitable to investigate turbid samples in a nondestructive and reproducible way, providing information on the static and dynamic rheological properties of the system [43]. Polystyrene latex particles with high surface density of carboxyl groups and with a mean size of 400 nm (PL6204-6101, Agilent Technologies, Santa Clara, CA, USA) were used as tracers, and added to the sample solution to a final concentration of 0.5% ( w / w ).…”

Cellulose as a Natural Emulsifier: From Nanocelluloses to Macromolecules

“…Moreover, the resulting emulsions are remarkably stable against environmental changes, such as, pH, ionic strength, and temperature, which makes them good candidates for target delivering [80,82,86]. Cellulose regenerated particles have also been shown to improve the physical stability of emulsions stabilized by sodium-caseinate, a milk-protein commonly used as a food emulsifier, promoting adsorption of the protein and thickening the continuous phase [87].…”