scholarly journals Nanoparticle-laden droplets of liquid crystals: Interactive morphogenesis and dynamic assembly

2019 ◽  
Vol 5 (7) ◽  
pp. eaav1035 ◽  
Author(s):  
Yunfeng Li ◽  
Nancy Khuu ◽  
Elisabeth Prince ◽  
Moien Alizadehgiashi ◽  
Elizabeth Galati ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Nanostructured Materials ◽  
Cellulose Nanocrystals ◽  
Liquid Crystalline ◽  
Shell Morphology ◽  
Core Shell ◽  
The Core ◽  
Defects In Liquid Crystals ◽  
Dynamic Assembly

Defects in liquid crystals serve as templates for nanoparticle (NP) organization; however, NP assembly in cholesteric (Ch) liquid crystals is only beginning to emerge. We show interactive morphogenesis of NP assemblies and a Ch liquid crystalline host formed by cellulose nanocrystals (CNCs), in which both the host and the guest experience marked changes in shape and structure as a function of concentration. At low NP loading, Ch-CNC droplets exhibit flat-ellipsoidal packing of Ch pseudolayers, while the NPs form a toroidal ring- or two cone–shaped assemblies at droplet poles. Increase in NP loading triggers reversible droplet transformation to gain a core-shell morphology with an isotropic core and a Ch shell, with NPs partitioning in the core and in disclinations. We show programmable assembly of droplets carrying magnetic NPs. This work offers a strategy for NP organization in Ch liquid crystals, thus broadening the spectrum of architectures of soft nanostructured materials.

Supramolecular Polymerization in Liquid Crystalline Media: Toward Modular Synthesis of Multifunctional Core–Shell Columnar Liquid Crystals

2019 ◽  
Vol 141 (25) ◽  
pp. 10033-10038 ◽  
Author(s):  
Keiichi Yano ◽  
Takahiro Hanebuchi ◽  
Xu-Jie Zhang ◽  
Yoshimitsu Itoh ◽  
Yoshiaki Uchida ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Core Shell ◽  
Modular Synthesis ◽  
Supramolecular Polymerization

scholarly journals Unravelling the interfacial interaction in mesoporous SiO2@nickel phyllosilicate/TiO2 core–shell nanostructures for photocatalytic activity

2020 ◽  
Vol 11 ◽  
pp. 1834-1846
Author(s):  
Bridget K Mutuma ◽  
Xiluva Mathebula ◽  
Isaac Nongwe ◽  
Bonakele P Mtolo ◽  
Boitumelo J Matsoso ◽  
...  
Keyword(s):  
Methyl Violet ◽  
Optoelectronic Properties ◽  
Shell Morphology ◽  
Bandgap Energy ◽  
Core Shell ◽  
The Core ◽  
Shell Nanostructures ◽  
Carrier Separation ◽  
First Time

Core–shell based nanostructures are attractive candidates for photocatalysis owing to their tunable physicochemical properties, their interfacial contact effects, and their efficacy in charge-carrier separation. This study reports, for the first time, on the synthesis of mesoporous silica@nickel phyllosilicate/titania (mSiO2@NiPS/TiO2) core–shell nanostructures. The TEM results showed that the mSiO2@NiPS composite has a core–shell nanostructure with a unique flake-like shell morphology. XPS analysis revealed the successful formation of 1:1 nickel phyllosilicate on the SiO2 surface. The addition of TiO2 to the mSiO2@NiPS yielded the mSiO2@NiPS/TiO2 composite. The bandgap energy of mSiO2@NiPS and of mSiO2@NiPS/TiO2 were estimated to be 2.05 and 2.68 eV, respectively, indicating the role of titania in tuning the optoelectronic properties of the SiO2@nickel phyllosilicate. As a proof of concept, the core–shell nanostructures were used as photocatalysts for the degradation of methyl violet dye and the degradation efficiencies were found to be 72% and 99% for the mSiO2@NiPS and the mSiO2@NiPS/TiO2 nanostructures, respectively. Furthermore, a recyclability test revealed good stability and recyclability of the mSiO2@NiPS/TiO2 photocatalyst with a degradation efficacy of 93% after three cycles. The porous flake-like morphology of the nickel phyllosilicate acted as a suitable support for the TiO2 nanoparticles. Further, a coating of TiO2 on the mSiO2@NiPS surface greatly affected the surface features and optoelectronic properties of the core–shell nanostructure and yielded superior photocatalytic properties.

Synthesis of Crosslinkable Core-Shell Emulsion and Rheology of the Core-Shell/Amine Crosslinking Process

2009 ◽  
Vol 79-82 ◽  
pp. 2203-2206
Author(s):  
Jia Lu ◽  
Allan J. Easteal ◽  
Debes Bhattacharyya ◽  
Clive J. Bolt ◽  
Neil R. Edmonds
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Complex Viscosity ◽  
Shell Morphology ◽  
Core Shell ◽  
Average Particle ◽  
Crosslinking Reaction ◽  
Shear Moduli ◽  
The Core ◽  
Wide Range

Starve feed and semi-continuous seed emulsion polymerization were used to control the morphology of core shell latex particles with a vinyl acetate (VAc)/vinyl ester of versatic acid 10(VeoVa10) copolymer core surrounded by a poly(glycidyl methacrylate) (PGMA) shell. Pure core and core-shell structures were confirmed by TEM. The results suggest that core-shell morphology of the two stage emulsion was favoured by higher concentration of emulsifier in the seed latex: the particle size distribution of core-shell latex was broader than that of the core latex, and the average particle size of core-shell latex was larger than that of the core latex. The core-shell structure was not produced using seed emulsion with emulsifier concentration at or below the critical micelle concentration. The core shell emulsion containing epoxy functional group with added ethylene diamine showed an abrupt increase in dynamic shear moduli, G' and G'' and complex viscosity η* (several orders of magnitude) at about 35oC, during temperature ramps, over a wide range of angular frequencies. The time ramps showed that the crosslinking reaction did not occur at 15oC for the core-shell emulsion/amine system. The time for gel formation decreased with increase in temperature.

Synthesis of Suitable SiO2 Nano Particles as the Core in Core–Shell Nanostructured Materials

2011 ◽  
Vol 11 (6) ◽  
pp. 5311-5317 ◽  
Author(s):  
Mehdi Ghahari ◽  
Roya Aghababazadeh ◽  
Touradj Ebadzadeh ◽  
Alireza Mirhabibi ◽  
Rik Brydson ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Nano Particles ◽  
Core Shell ◽  
The Core

Nematic-to-columnar mesophase transition by in situ supramolecular polymerization

Science ◽  
2019 ◽  
Vol 363 (6423) ◽  
pp. 161-165 ◽  
Author(s):  
Keiichi Yano ◽  
Yoshimitsu Itoh ◽  
Fumito Araoka ◽  
Go Watanabe ◽  
Takaaki Hikima ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Liquid Crystalline ◽  
Crystalline Material ◽  
Core Shell ◽  
Condensed Phases ◽  
Supramolecular Polymerization ◽  
Liquid Crystalline Material

Disk- and rod-shaped molecules are incompatible in coassembly, as the former tend to stack one-dimensionally whereas the latter tend to align in parallel. Because this type of incompatibility can be more pronounced in condensed phases, different-shaped molecules generally exclude one another. We report that supramolecular polymerization of a disk-shaped chiral monomer in nematic liquid crystals comprising rod-shaped molecules results in order-increasing mesophase transition into a single mesophase with a core-shell columnar geometry. This liquid crystalline material responds quickly to an applied electric field, resulting in unidirectional columnar ordering. Moreover, it can be modularly customized to be optoelectrically responsive simply by using a photoisomerizable rod-shaped module. The modular strategy allows for cooperative integration of different functions into elaborate dynamic architectures.

Core/Shell Nanostructured Materials for Sustainable Processes

2016 ◽  
Vol 14 (3) ◽  
pp. 667-684 ◽  
Author(s):  
Zhenkun Sun ◽  
Serge Kaliaguine
Keyword(s):  
Nanostructured Materials ◽  
Shell Structure ◽  
Materials Design ◽  
Simple Solution ◽  
Core Shell ◽  
Design Problems ◽  
Structured Materials ◽  
The Core ◽  
Potential Applications ◽  
Core Shell Structure

Abstract In this paper, we summarize recent research efforts from our laboratory concerning the application of core/shell structured materials for sustainability. Special attention is paid to the synthesis of different core/shell materials from nanoscale to microscale by various methods. The potential applications of our prepared novel materials with core/shell configuration are discussed, which illustrates the diversity of situations where the core/shell structure brings a simple solution to different materials design problems.

scholarly journals Preparation and Deep Characterization of Composite/Hybrid Multi-Scale and Multi-Domain Polymeric Microparticles

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3921 ◽  
Author(s):  
Wei Yu ◽  
Nikunjkumar Visaveliya ◽  
Christophe A. Serra ◽  
J. Michael Köhler ◽  
Shukai Ding ◽  
...  
Keyword(s):  
Miniemulsion Polymerization ◽  
Elongational Flow ◽  
Water Soluble ◽  
Shell Morphology ◽  
Core Shell ◽  
X Rays ◽  
Multi Scale ◽  
The Core ◽  
Step Procedure ◽  
Polymeric Microparticles

Polymeric microparticles were produced following a three-step procedure involving (i) the production of an aqueous nanoemulsion of tri and monofunctional acrylate-based monomers droplets by an elongational-flow microemulsifier, (ii) the production of a nanosuspension upon the continuous-flow UV-initiated miniemulsion polymerization of the above nanoemulsion and (iii) the production of core-shell polymeric microparticles by means of a microfluidic capillaries-based double droplets generator; the core phase was composed of the above nanosuspension admixed with a water-soluble monomer and gold salt, the shell phase comprised a trifunctional monomer, diethylene glycol and a silver salt; both phases were photopolymerized on-the-fly upon droplet formation. Resulting microparticles were extensively analyzed by energy dispersive X-rays spectrometry and scanning electron microscopy to reveal the core-shell morphology, the presence of silver nanoparticles in the shell, organic nanoparticles in the core but failed to reveal the presence of the gold nanoparticles in the core presumably due to their too small size (c.a. 2.5 nm). Nevertheless, the reddish appearance of the as such prepared polymer microparticles emphasized that this three-step procedure allowed the easy elaboration of composite/hybrid multi-scale and multi-domain polymeric microparticles.

scholarly journals Acetylene hydrogenation over structured Au–Pd catalysts

2016 ◽  
Vol 188 ◽  
pp. 499-523 ◽  
Author(s):  
Alan J. McCue ◽  
Richard T. Baker ◽  
James A. Anderson
Keyword(s):  
Shell Morphology ◽  
Shell Structures ◽  
Core Shell ◽  
Shell Layer ◽  
Pd Catalysts ◽  
Acetylene Hydrogenation ◽  
The Core ◽  
Selective Hydrogenation Of Acetylene ◽  
Core Shell Structure ◽  
Improved Performance

AuPd nanoparticles were prepared following a methodology designed to produce core–shell structures (an Au core and a Pd shell). Characterisation suggested that slow addition of the shell metal favoured deposition onto the pre-formed core, whereas more rapid addition favoured the formation of a monometallic Pd phase in addition to some nanoparticles with the core–shell morphology. When used for the selective hydrogenation of acetylene, samples that possessed monometallic Pd particles favoured over-hydrogenation to form ethane. A sample prepared by the slow addition of a small amount of Pd resulted in the formation of a core–shell structure but with an incomplete Pd shell layer. This material exhibited a completely different product selectivity with ethylene and oligomers forming as the major products as opposed to ethane. The improved performance was thought to be as a result of the absence of Pd particles, which are capable of forming a Pd-hydride phase, with enhanced oligomer selectivity associated with reaction on uncovered Au atoms.

Sign in / Sign up

Export Citation Format

Share Document