Origin of stabilisation of aqueous foams in nanoparticle–surfactant mixtures

By B. Binks, M. Kirkland, J. Rodrigues. 2008

267 citations recorded by the source corpus.

Using a range of complementary experiments, a detailed investigation into the behaviour of air-in-water foams stabilised by a mixture of silica nanoparticles and pure cationic surfactant has been made. At high pH where particles are significantly negatively charged and surfactant is positively charged, no foam is possible with particles alone whereas surfactant-stabilised foams break down completely within one day at all concentrations. In particle–surfactant mixtures, a synergism occurs with respect to foam formation and stability due to the adsorption of surfactant molecules onto particle surfaces. The foamability of mixed dispersions is substantially reduced compared with surfactant solutions alone. However, the foam stability passes through a maximum with respect to surfactant concentration and these foams are remarkably stable. Based on our findings from dispersion stability measurements, particle ζ potentials, the adsorption isotherm of surfactant on particles and relevant contact angles of water in air on silica surfaces, we conclude that foams are most stable when particles are strongly flocculated corresponding to them possessing a low charge, being maximally hydrophobic and containing an adsorbed monolayer of surfactant. Cryo-scanning electron microscopy (cryo-SEM) analysis of the same foams leads us to propose that foam stabilisation changes from being surfactant dominated at low surfactant concentration to being particle dominated at intermediate concentrations and reverting to surfactant dominated at higher concentrations.

Subfields: Materials Chemistry, Ocean Engineering, Organic Chemistry

View Paper: https://www.semanticscholar.org/paper/cd765b741af91b6ebd68dfceb359b885d7cd0288

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Materials Chemistry

1. R. Rubio
2. F. Ortega
3. E. Guzmán
4. Yunpeng Li
5. Lixin Wang
6. Siavash Riahi
7. Hamed Farhadi
8. Xiuling Wang

In Organic Chemistry

1. R. Rubio
2. F. Ortega
3. E. Guzmán
4. Siavash Riahi
5. Hamed Farhadi
6. S. Ayatollahi
7. A. Maestro
8. H. Ahmadi

Citations in the corpus

• Foam Concrete: A State-of-the-Art and State-of-the-Practice Review (2020, background): “[185] revealed that the stability of bubbles formed by the mixed system of SiO2 and cetyltrimethylammonium bromide (CTAB) was significantly higher than that in the single CTAB system, but the foaming property was slightly weaker.”
• Experimental study of nanoparticle-surfactant-stabilized CO2 foam: Stability and mobility control (2016, background): “This is also a valid comparison between surfactant and nanoparticles (Binks et al., 2008; Nguyen et al., 2014).”
• Contact angle of micro- and nanoparticles at fluid interfaces (2014, background): “[80] Binks BP, Kirkland M, Rodrigues JA.”