Related Experiment Video
Updated: Dec 6, 2025
Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation
Published on: August 28, 2017
Dynamic emulsion droplets enabled by interfacial assembly of azobenzene-functionalized nanoparticles under light and
Guangbin Ji1, Fei Yang2, Yanzhao Yang1
1Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China.
Hypothesis:
The ability to control the assembly of micro/nanosized particles at liquid-liquid interface with external inputs promises new opportunities in nanofabrication and biomedicines. This work aims to demonstrate a way to control of dynamic assembly of nanoparticles at liquid-liquid interface by light and magnetic field, which consequently enables the formation of dynamic emulsion droplets.
Experiments:
Magnetic Fe3O4 nanoparticles functionalized with azobenzene moieties (Fe3O4@AZO) were synthesized and were dispersed in toluene/(N,N-dimethylformamide, DMF) binary solvent. After irradiation with UV or visible light, the assembly behavior of these Fe3O4 nanoparticles were evaluated by electron microscopy and fluorescent microscopy.
Findings:
Under UV light, Fe3O4@AZO nanoparticles were self-assembled due to the increase of dipolar interaction from the photoisomerization of azobenzene and polar molecules, DMF, were harvested from a binary solvent of DMF/toluene. While under visible light, a relief of dipolar interactions between Fe3O4@AZO nanoparticles can induce the secondary assembly of these Fe3O4@AZO nanoparticles at DMF-toluene interface, resulting in DMF droplets covered by a layer of nanoparticle superlattices. More importantly, coupled with a magnetic field, these emulsion droplets can be shaped into one dimensional ones during the interfacial assembly process, thereby giving rise to dynamic emulsions controlled by light and magnetic field.
