Gelation in Oleogels: A Rheological Framework for Soft Material Formulation.

Area of Science:

• Materials Science
• Physical Chemistry
• Rheology

Background:

• Oleogels from natural waxes exhibit a sol-gel transition upon cooling, driven by crystalline network formation.
• The interfacial properties of wax crystals significantly influence the bulk viscoelastic behavior of oleogels.
• Critical gelation theory has not been previously applied to understand this sol-gel transition in wax-based oleogels.

Purpose of the Study:

• To investigate the sol-gel transition in beeswax-corn oil oleogels using critical gelation theory.
• To establish a unified linear viscoelastic description for the sol-gel transition in these oleogels.
• To develop a framework for manipulating oleogel properties for specific applications.

Main Methods:

• Detailed linear viscoelastic analysis under oscillatory shear flow.
• Temperature-dependent dynamic moduli measurements.
• Analysis of scaling relations and fractal dimensions.

Main Results:

• Identified a critical gel state characterized by frequency-independent dynamic moduli.
• Validated critical gelation theory through hyperscaling relations of scaling exponents.
• Quantified the impact of wax concentration on fractal dimension and gel strength.

Conclusions:

• This study provides the first comprehensive validation of critical gelation theory for wax-based oleogels.
• A predictive framework for oleogel formulation and processing near the gel point is established.
• A design framework for tuning oleogel mechanical stiffness and thermal durability is presented.