Imaging of phase change materials below a capping layer using correlative infrared near-field microscopy and electron microscopy

AbstractLauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

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Controlling the near-field excitation of nano-antennas with phase-change materials

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.4.70 ◽

2013 ◽

Vol 4 ◽

pp. 632-637 ◽

Cited By ~ 8

Author(s):

Tsung Sheng Kao ◽

Yi Guo Chen ◽

Ming Hui Hong

Keyword(s):

Thin Layer ◽

Phase Change ◽

Hot Spots ◽

Phase Change Materials ◽

Near Field ◽

Plasmon Coupling ◽

New Approach ◽

Field Excitation ◽

Bio Assay ◽

Nano Antennas

By utilizing the strongly induced plasmon coupling between discrete nano-antennas and quantitatively controlling the crystalline proportions of an underlying Ge2Sb2Te5 (GST) phase-change thin layer, we show that nanoscale light localizations in the immediate proximity of plasmonic nano-antennas can be spatially positioned. Isolated energy hot-spots at a subwavelength scale can be created and adjusted across the landscape of the plasmonic system at a step resolution of λ/20. These findings introduce a new approach for nano-circuitry, bio-assay addressing and imaging applications.

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Optical Forces on an Oscillating Dipole Near VO2 Phase Transition

Universe ◽

10.3390/universe7060159 ◽

2021 ◽

Vol 7 (6) ◽

pp. 159

Author(s):

Daniela Szilard ◽

Patrícia P. Abrantes ◽

Felipe A. Pinheiro ◽

Felipe S. S. Rosa ◽

Carlos Farina ◽

...

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Thermal Hysteresis ◽

Dipole Moments ◽

Near Field ◽

Optical Forces ◽

Similar System ◽

Magnetic Dipoles ◽

Thermochromic Material ◽

Control Light

We investigate optical forces on oscillating dipoles close to a phase change vanadium dioxide (VO2) film, which exhibits a metal-insulator transition around 340 K and low thermal hysteresis. This configuration emulates the interaction between an illuminated nanosphere and an interface and we employ a classical description to capture its important aspects. We consider both electric and magnetic dipoles for two different configurations, namely with the dipole moments parallel and perpendicular to the VO2 film. By using Bruggeman theory to describe the effective optical response of the material, we show that the thermal hysteresis present in the VO2 transition clearly shows up in the behavior of optical forces. In the near-field regime, the force on both dipoles can change from attractive to repulsive just by heating (or cooling) the film for a selected frequency range. We also verified that the optical forces are comparable to the Casimir-Polder force in a similar system, revealing the possibility of modulating or even changing the sign of the resultant force on an illuminated nano-object due to the presence of a thermochromic material. We hope that this work contributes to set the grounds for alternative approaches to control light-matter interactions using phase-change materials.

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Computations with near-field coupled plasmon particles interacting with phase-change materials

Applied Physics A ◽

10.1007/s00339-015-9338-2 ◽

2015 ◽

Vol 121 (4) ◽

pp. 1323-1327 ◽

Cited By ~ 2

Author(s):

Shohei Kanazawa ◽

Kenta Kuwamura ◽

Yuya Kihara ◽

Yusuke Hirukawa ◽

Toshiharu Saiki

Keyword(s):

Phase Change ◽

Phase Change Materials ◽

Near Field

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Thermal Properties and Morphology of Electrospun PEG/PVP Composite Fibers as Novel Phase Change Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.3998 ◽

2012 ◽

Vol 204-208 ◽

pp. 3998-4001

Author(s):

Qi Song Shi

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Differential Scanning Calorimetry ◽

Thermal Properties ◽

Phase Change ◽

Phase Change Materials ◽

Composite Fibers ◽

Scanning Calorimetry ◽

Ultrafine Fibers ◽

Scanning Electron

The ultrafine fibers based on the composites of polyethylene glycol(PEG) and polyvinylpyrrolidone(PVP) were prepared successfully via electrospinning as phase change materials. The thermal properties and morphology of the composite fibers were studied by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM), respectively.

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Preparation of Phase Change Building Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.96.161 ◽

2010 ◽

Vol 96 ◽

pp. 161-164

Author(s):

Hai Jian Li ◽

Zhi Jiang Ji ◽

Zhi Jun Xin ◽

Jing Wang

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Phase Change ◽

Building Materials ◽

Phase Change Materials ◽

Absorption Method ◽

Scanning Calorimetry ◽

Steady Temperature ◽

Scanning Electron ◽

High Latent Heat

The types and characteristics of phase change materials were discussed. With respect to application in building materials, the PCM should have more attractive properties including high latent heat values, stability and proper melting point, inflammability, corrosiveness and supercooling. Phase change building material (PCBM) was prepared using vacuum absorption method and tested by means of Differential Scanning Calorimetry(DSC) and Scanning Electron Microscopy(SEM). The testing results have shown that organic PCM was absorbed into the holes of inorganic carriers completely and distributed evenly with stable performances. It is concluded that the composite PCM has steady temperature-adjusting function and the preparation means is acceptable.

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