TY - JOUR

T1 - Non-Classical Self-Assembly of Anisotropic Magneto-Organosilica Janus Particles Possessing Surfactant Properties and the Field-Triggered Breakdown of Surface Activity and Amphiphilic Properties

AU - Lanz, Cornelia

AU - Krysiak, Yaşar

AU - Liu, Xu

AU - Hohgardt, Manuel

AU - Walla, Peter Jomo

AU - Polarz, Sebastian

N1 - Funding Information: Part of this work was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) under Germany's excellence strategy within the cluster of excellence PhoenixD (EXC 2122).

PY - 2023/12/27

Y1 - 2023/12/27

N2 - Using colloidal particles as models to understand processes on a smaller scale is a precious approach. Compared to molecules, particles are less defined, but their architecture can be more complex and so is their long-range interaction. One can observe phenomena that are unknown or much more difficult to realize on the molecular level. The current paper focuses on particle-based surfactants and reports on numerous unexpected properties. The main goal is creating an amphiphilic system with responsiveness in surface activity and associated self-organization phenomena depending on applying an external trigger, preferably a physical field. A key step is the creation of a Janus-type particle characterized by two types of dipoles (electric and magnetic) which geometrically stand orthogonal to each other. In a field, one can control which contribution and direction dominate the interparticle interactions. As a result, one can drastically change the system's properties. The features of ferrite-core organosilica-shell particles with grain-like morphology modified by click chemistry are studied in response to spatially isotropic and anisotropic triggers. A highly unusual aggregation–dissolution–reaggregation sequence w as discovered. Using a magnetic field, one can even switch off the amphiphilic properties and use this for the field-triggered breaking of multiphase systems such as emulsions.

AB - Using colloidal particles as models to understand processes on a smaller scale is a precious approach. Compared to molecules, particles are less defined, but their architecture can be more complex and so is their long-range interaction. One can observe phenomena that are unknown or much more difficult to realize on the molecular level. The current paper focuses on particle-based surfactants and reports on numerous unexpected properties. The main goal is creating an amphiphilic system with responsiveness in surface activity and associated self-organization phenomena depending on applying an external trigger, preferably a physical field. A key step is the creation of a Janus-type particle characterized by two types of dipoles (electric and magnetic) which geometrically stand orthogonal to each other. In a field, one can control which contribution and direction dominate the interparticle interactions. As a result, one can drastically change the system's properties. The features of ferrite-core organosilica-shell particles with grain-like morphology modified by click chemistry are studied in response to spatially isotropic and anisotropic triggers. A highly unusual aggregation–dissolution–reaggregation sequence w as discovered. Using a magnetic field, one can even switch off the amphiphilic properties and use this for the field-triggered breaking of multiphase systems such as emulsions.

KW - active colloids

KW - Janus nanostructures

KW - magnetic surfactants

KW - particle-based materials

UR - http://www.scopus.com/inward/record.url?scp=85169325005&partnerID=8YFLogxK

U2 - 10.1002/smll.202304380

DO - 10.1002/smll.202304380

M3 - Article

AN - SCOPUS:85169325005

VL - 19

JO - SMALL

JF - SMALL

SN - 1613-6810

IS - 52

M1 - 2304380

ER -