http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Synergistic assembly of nanoparticles in smectic liquid crystals
Honglawan, Apiradee,Kim, Dae Seok,Beller, Daniel A.,Yoon, Dong Ki,Gharbi, Mohamed A.,Stebe, Kathleen J.,Kamien, Randall D.,Yang, Shu The Royal Society of Chemistry 2015 SOFT MATTER Vol.11 No.37
<P>We report synergistic co-assembly between smectic A liquid crystal (SmA LC) and planar anchoring fluorosilane functionalized silica (F-SiO<SUB>2</SUB>) nanoparticles (NPs). Both scanning electron microscope (SEM) images and grazing incidence X-ray diffraction (GIXD) patterns show that when cooled from the isotropic phase to SmA phase, F-SiO<SUB>2</SUB> NPs (100–500 nm in diameter) migrate from the bottom to the top of the LC film through the central cusp defects of toric focal conic domains (TFCDs). When the NPs form a monolayer on top, replacing the LC/air interface, vertically aligned SmA layers are formed between the top and bottom planar surfaces. When F-SiO<SUB>2</SUB> NP diameter is small (<500 nm), we observe a weak-anchoring regime, where NPs do not cause appreciable layer curvature and NP migration is driven by surface energy. When F-SiO<SUB>2</SUB> particle diameter > 500 nm, strong distortions occur in the smectic layers, and the particle is found suspended at the TFCD defect core. The knowledge of the intermediate states of the NP/LC hybrid structures will provide valuable insights to assemble functional nanomaterials such as quantum dots and metallic NPs in an anisotropic medium, and take advantage of their collective assembly behaviors to create more complex and dynamic structures.</P> <P>Graphic Abstract</P><P>When cooled from the isotropic phase to smectic A phase of liquid crystals (LCs), planar anchoring SiO<SUB>2</SUB> nanoparticles migrate as a group through the central cusp defects of toric focal conic domains, leading to the formation of vertically aligned LC layers between the top and bottom planar surfaces. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5sm01458a'> </P>
Creation of nano-particle-clusters array using sublimable liquid crystal
김대석,( Apiradee Honglawan ),김경남,김문호,정소희,윤동기 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
Here, we have demonstrated, for the first time, that NP clusters array in large area for F-SiO2 (d: 100nm) and QD, CdSe (d: 10nm) by using the transforming TFCDs as a template for directed self-clustering of NPs during thermal annealing. This process is mainly governed by the topological effect of the dimple like defects of TFCDs to confine the NPs with macroscopic array and the sublimation and reconstruction phenomenon to effectively form spherical NP clusters. Thus, we have confirmed the formation of NP clusters array using scanning electron microscopy (SEM) and fluorescence microscopy (FM) as well as investigated the mechanism using SEM and depolarized reflective light microscopy (DRLM) as function of thermal annealing times. This approach provides a simple and novel way to control NPs clustering and its macroscopic array in large area. Furthermore, this system may open a new clusters array system for various NP types to generate interesting opto-electric properties.
Fabrication of periodic nanoparticle clusters using a soft lithographic template
Kim, Dae Seok,Honglawan, Apiradee,Kim, Kyungnam,Kim, Mun Ho,Jeong, Sohee,Yang, Shu,Yoon, Dong Ki The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.18
<▼1><P>A novel fabrication method has been developed for the preparation of a periodic array of nanoparticle clusters (NPCs) using a sublimable liquid crystal (LC) material.</P></▼1><▼2><P>A novel fabrication method has been developed for the preparation of a periodic array of nanoparticle clusters (NPCs) using a sublimable liquid crystal (LC) material. The defect structures of the LC film provide the specific topographical confinement to trap nanoparticles (NPs) and assemble the NPs to generate NPCs during thermal annealing. This system shows a simple regulation of the size of NPCs by varying the concentration of the NP-suspension. Additionally, an illumination system using quantum dots (QDs) is fabricated using the manipulation method reported here.</P></▼2>
Arrangement and SERS Applications of Nanoparticle Clusters Using Liquid Crystalline Template
Kim, Dae Seok,Honglawan, Apiradee,Yang, Shu,Yoon, Dong Ki American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.8
<P>Manipulation of nanomaterials such as nanoparticles (NPs) and nanorods (NRs) to make clusters is of significant interest in material science and nanotechnology due to the unusual collective opto-electric properties in such structures that cannot be found in the individual NPs. This work demonstrates an effective way to arrange NP clusters (NPCs) to make the desired arrays based on removable and NP-guidable liquid crystalline template using sublimation and reconstruction phenomenon. The position of the NPCs is precisely controlled by the defect structure of the liquid crystal (LC), namely toric focal conic domains (TFCDs), during thermal annealing to construct the LC and corresponding NPC structures. As a proof of concept, the surface-enhanced Raman scattering (SERS) activity of a fabricated array of gold nanorod (GNR) clusters is measured and shown to have highly sensitive detection characteristics essential for potential sensing applications.</P>