pH-responsive aqueous foams stabilized by hairy latex particles
Syuji Fujii1, Michiru Mochizuki, Kodai Aono
1Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Ohmiya, Asahi-ku, Osaka 535-8585, Japan. s.fujii@chem.oit.ac.jp
Langmuir : the ACS Journal of Surfaces and Colloids
|September 14, 2011
Summary
pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairs on polystyrene (PS) particles stabilize aqueous foams. These PDEA-PS particles can be repeatedly used for foam stabilization and rapid defoaming by adjusting pH.
Area of Science:
- Colloid and Surface Science
- Polymer Chemistry
- Materials Science
Background:
- Foam stabilization is crucial in various industrial processes.
- Developing responsive materials for controlled foam behavior is an active research area.
- pH-responsive polymers offer tunable properties based on environmental acidity.
Purpose of the Study:
- To synthesize and characterize pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) grafted polystyrene (PS) latex particles.
- To investigate the ability of these PDEA-PS particles to stabilize aqueous foams.
- To explore the pH-dependent foaming and defoaming capabilities of the synthesized particles.
Main Methods:
- Dispersion polymerization for synthesizing PDEA-PS particles.
- Characterization using SEM, elemental microanalysis, NMR, laser diffraction, and zeta potential measurements.
- Foam stability tests at various pH values and microscopic analysis of particle adsorption at the air-water interface.
Main Results:
- PDEA-PS particles demonstrated pH-dependent foam stabilization, with stable foams observed above pH 8.0.
- Particles adsorbed as a monolayer at the air-water interface at pH 6.1, stabilizing foams for at least 24 hours.
- Foam formation was inhibited at pH 5.1 and 3.1 due to protonation and increased hydrophilicity of PDEA hairs.
- Rapid defoaming was achieved by lowering pH, and the foaming-defoaming cycles were repeatable.
Conclusions:
- PDEA-PS particles act as effective pH-responsive stabilizers for aqueous foams.
- The tunable hydrophobicity/hydrophilicity of PDEA hairs allows for controlled foam formation and destruction.
- These particles offer potential for applications requiring reversible foam control.
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