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Published on: February 19, 2016
Nanoscale aggregate structures of trisiloxane surfactants at the solid-liquid interface
Jinping Dong1, Guangzhao Mao, Randal M Hill
1Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 20, 2005
Summary
This study reveals how trisiloxane surfactants (BEn) form structures at interfaces, correlating their behavior with superwetting properties on various substrates. Their adsorption is similar to other surfactants, confirming shared superwetting features.
Area of Science:
- Surface Chemistry
- Materials Science
- Colloid and Surface Chemistry
Background:
- Nonionic trisiloxane surfactants, known as superwetters, facilitate rapid spreading of aqueous solutions on low-energy surfaces.
- Understanding their self-associating structures at solid-liquid interfaces is crucial for optimizing their applications.
Purpose of the Study:
- To investigate the self-associating structures of BEn surfactants at solid-liquid interfaces.
- To correlate these structures with their superwetting behavior across different substrates.
- To understand the adsorption mechanisms and compare them with other surfactant classes.
Main Methods:
- Atomic Force Microscopy (AFM) imaging and force measurements were employed.
- Four distinct substrates were used: muscovite mica, highly oriented pyrolytic graphite (HOPG), and oxidized silicon wafers (with and without n-octadecyltrichlorosilane (OTS) monolayers).
- Surfactant concentration was fixed at 2 times the critical aggregation concentration (CAC).
Main Results:
- BEn surfactants showed weak attraction to hydrophilic surfaces, with stronger adsorption on oxidized silicon than mica.
- Planar monolayers were formed on HOPG and OTS-covered oxidized silicon.
- Surface aggregate structures correlated with bulk structures, indicating no anomalous adsorption.
- AFM tip adsorption effects were investigated using thiol-modified tips.
Conclusions:
- The surface aggregate structures of BEn surfactants are consistent with their bulk properties and do not exhibit unusual adsorption.
- The adsorption behavior of BEn superwetters is comparable to CmEn surfactants.
- Superwetting properties share key characteristics with other surfactant classes, validating previous findings.
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