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Microfluidic Preparation of Liquid Crystalline Elastomer Actuators
Published on: May 20, 2018
Coalescence control of elastomer clusters by fixed surface charges
Cornelius Gauer1, Hua Wu, Massimo Morbidelli
1Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
The Journal of Physical Chemistry. B
|January 9, 2010
Summary
Temperature increases the coalescence of fluorinated elastomer colloids. This is due to reduced kinetic resistance from surface charges, not thermodynamics, enhancing aggregation under diffusion-limited cluster-cluster aggregation conditions.
Area of Science:
- Colloid Science
- Polymer Chemistry
- Physical Chemistry
Background:
- Fluorinated elastomers are used in various applications requiring specific surface properties.
- Colloid aggregation kinetics are influenced by interparticle forces and environmental conditions.
- Understanding coalescence is crucial for controlling material properties in colloidal systems.
Purpose of the Study:
- To investigate the temperature-dependent coalescence behavior of fluorinated elastomer colloids.
- To determine the fractal dimension of aggregated clusters under diffusion-limited cluster-cluster aggregation (DLCA) conditions.
- To elucidate the underlying mechanisms governing temperature-induced changes in coalescence.
Main Methods:
- In situ dynamic light scattering (DLS) to measure aggregation kinetics.
- Smoluchowski approach (population balance equations) for simulation.
- Fitting simulation data using the fractal dimension (D(f)) as a parameter.
Main Results:
- The fractal dimension (D(f)) of clusters increased with temperature, from 1.7 at 25°C to 3.0 at ≥55°C.
- Colescence extent was found to increase significantly as temperature rose.
- Observed behavior deviates from purely thermodynamic explanations.
Conclusions:
- Temperature plays a critical role in the coalescence of these fluorinated elastomer colloids.
- The increased coalescence is attributed to decreased kinetic resistance of surface charges at higher temperatures.
- This finding highlights the importance of kinetic factors in controlling colloidal aggregation.
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