Core–shell colloidal particles with dynamically tunable scattering properties

Soft Matter ◽  
2017 ◽  
Vol 13 (37) ◽  
pp. 6293-6296 ◽  
Author(s):  
Guangnan Meng ◽  
Vinothan N. Manoharan ◽  
Adeline Perro

Polystyrene-hydrogel core–shell particles exhibiting a transition from Rayleigh to Mie scattering are created. Optical measurements show that the transition is controlled by varying temperature or ionic strength. Such core–shell particles may find use as optical switches or optical filters with tunable opacity.

2005 ◽  
Vol 70 (3) ◽  
pp. 361-369 ◽  
Author(s):  
M.D. Lechner

Nanoparticles are used in large quantities for very different applications. A precise determination of the diameter and the particle size distribution which is responsible for the application properties is therefore essential. Reliable methods for measuring the above mentioned quantities are photometric measurements and analytical ultracentrifugation with an UV optics detector. Both methods are ruled by the Mie effect, that is scattering and absorption of the particles as function of the diameter, the wavelength, and the shape of the particles. The extinction coefficients ?=?/c for spheres, rods, and core shell particles have been calculated and plotted over a wide range of the size parameter ?d/?. Two examples for multimodal latex particles and core shell particles have been given and demonstrate the applicability of the method.


2021 ◽  
Vol 118 (52) ◽  
pp. e2113394118
Author(s):  
Johannes Menath ◽  
Jack Eatson ◽  
Robert Brilmayer ◽  
Annette Andrieu-Brunsen ◽  
D. Martin A. Buzza ◽  
...  

The two-dimensional self-assembly of colloidal particles serves as a model system for fundamental studies of structure formation and as a powerful tool to fabricate functional materials and surfaces. However, the prevalence of hexagonal symmetries in such self-assembling systems limits its structural versatility. More than two decades ago, Jagla demonstrated that core–shell particles with two interaction length scales can form complex, nonhexagonal minimum energy configurations. Based on such Jagla potentials, a wide variety of phases including cluster lattices, chains, and quasicrystals have been theoretically discovered. Despite the elegance of this approach, its experimental realization has remained largely elusive. Here, we capitalize on the distinct interfacial morphology of soft particles to design two-dimensional assemblies with structural complexity. We find that core–shell particles consisting of a silica core surface functionalized with a noncrosslinked polymer shell efficiently spread at a liquid interface to form a two-dimensional polymer corona surrounding the core. We controllably grow such shells by iniferter-type controlled radical polymerization. Upon interfacial compression, the resulting core–shell particles arrange in well-defined dimer, trimer, and tetramer lattices before transitioning into complex chain and cluster phases. The experimental phase behavior is accurately reproduced by Monte Carlo simulations and minimum energy calculations, suggesting that the interfacial assembly interacts via a pairwise-additive Jagla-type potential. By comparing theory, simulation, and experiment, we narrow the Jagla g-parameter of the system to between 0.9 and 2. The possibility to control the interaction potential via the interfacial morphology provides a framework to realize structural features with unprecedented complexity from a simple, one-component system.


2010 ◽  
Vol 93-94 ◽  
pp. 27-30 ◽  
Author(s):  
Ha Soo Hwang ◽  
Duck Soo Yuk ◽  
So Hee Ko ◽  
In Park

Silica-coated raspberry-like polymeric particles were synthesized based on the cationic colloidal particles which were prepared by soap-free emulsion polymerization of methylmethacrylate (MMA) in the presence of a cationic monomer, methacryloxyethyltrimethyl ammonium chloride (MOTAC) using azobis(isobutylamidine)hydrochloride (AIBA) as an initiator. The Stöber method has been adopted to coat silica on the surface of these cationic particles. Negatively charged Silica precursors were rapidly hydrolyzed onto the cationic surfaces of colloidal particles. The resulted polymethylmethacrylate-silica(PMMA-silica) core-shell particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which clearly revealed that the PMMA-silica core-shell particles had the raspberry-like structure with 45nm wall thickness. Then, the fabrication of a superhydrophobic particle surface was achieved by coupling reaction of the PMMA-silica core-shell particle surface with nonafluorohexyltriethoxysilane. The water and oil static contact angle on the surface of the submicron-nano particles were 161° and 129°, respectively.


2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.


2008 ◽  
Vol 20 (4) ◽  
pp. 1292-1298 ◽  
Author(s):  
M. P. L. Werts ◽  
M. Badila ◽  
C. Brochon ◽  
A. Hébraud ◽  
G. Hadziioannou

Nano Letters ◽  
2014 ◽  
Vol 14 (4) ◽  
pp. 2140-2149 ◽  
Author(s):  
Maria E. Stournara ◽  
Yue Qi ◽  
Vivek B. Shenoy

2016 ◽  
Vol 8 (15) ◽  
pp. 3061-3068 ◽  
Author(s):  
Christina Meisenbichler ◽  
Julia S. Rauch ◽  
Yüksel Güzel ◽  
Eva-Maria Wernig ◽  
Dieter Schemeth ◽  
...  

Selective enrichment of phosphorylated peptides by magnetic ytterbium oxide core-shell particles.


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