Related Experiment Video
Updated: May 12, 2026
09:55
Preparation of Janus Particles and Alternating Current Electrokinetic Measurements with a Rapidly Fabricated Indium Tin Oxide Electrode Array
Published on: June 23, 2017
Micrometer-sized gold-silica Janus particles as particulate emulsifiers.
Syuji Fujii1, Yuichi Yokoyama, Yuki Miyanari
1Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, Asahi-ku, Osaka, Japan. s.fujii@chem.oit.ac.jp
Langmuir : the ACS Journal of Surfaces and Colloids
|April 27, 2013
Summary
Gold-silica Janus particles effectively stabilize emulsions for over a year by adsorbing at oil-water interfaces. This offers superior stability compared to silica particles, enabling novel microsphere fabrication.
Area of Science:
- Materials Science
- Colloid and Surface Chemistry
- Nanotechnology
Background:
- Emulsion stabilization is crucial in various industries.
- Traditional stabilizers often face limitations in long-term stability and environmental impact.
- Janus particles, with distinct surface properties, offer potential for advanced interfacial applications.
Purpose of the Study:
- To investigate the efficacy of gold-silica Janus particles in stabilizing oil-in-water emulsions.
- To compare the stabilization performance of Janus particles with bare silica particles.
- To explore the fabrication of polymer microspheres using Janus particle-stabilized emulsions.
Main Methods:
- Synthesis of micrometer-sized gold-silica Janus particles.
- Adsorption of Janus particles at the oil-water interface to form a monolayer.
- Preparation and characterization of emulsions stabilized by Janus particles and bare silica particles.
- Suspension polymerization of vinyl monomers within Janus particle-stabilized droplets.
Main Results:
- Janus particles effectively stabilized emulsions, maintaining droplet integrity for over a year.
- Janus particle-stabilized emulsions exhibited significantly greater stability than those stabilized by bare silica particles.
- The enhanced stability was attributed to the higher adsorption energy of Janus particles at the interface.
- Nonspherical polymer microspheres with Janus particles on their surface were successfully synthesized.
- Subsequent removal of the silica component yielded polymer microspheres with gold femtoliter cups.
Conclusions:
- Gold-silica Janus particles are highly effective stabilizers for long-term emulsion applications.
- The unique amphiphilic nature and strong interfacial adsorption of Janus particles are key to their performance.
- Janus particle-stabilized emulsions provide a versatile platform for fabricating functional polymer microspheres and nanostructures.
Related Concept Videos
03:22Colloids
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles that are visible to the naked eye or can be seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. On the other hand, a solution is a homogeneous mixture in which no settling occurs and in which the dissolved...
01:09Colloidal precipitates
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...