scholarly journals Synthesis and Properties of Inositol Nanocapsules

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5481
Author(s):  
Songping Mo ◽  
Yuanhong Li ◽  
Shaofei Shan ◽  
Lisi Jia ◽  
Ying Chen
Keyword(s):  
Electron Microscope ◽  
Phase Change ◽  
Phase Change Materials ◽  
Synthesis Conditions ◽  
Sio2 Shell ◽  
Transmission Electron ◽  
Supercooling Degree ◽  
Change Characteristics ◽  
Ir Transmission ◽  
Energy Storage Efficiency

Sugar alcohols are phase−change materials with various advantages but may suffer from leakage during applications. In this study, inositol nanocapsules were synthesized at various conditions, including the amount of precursors and the time for adding the precursors. The effects of synthesis conditions on the properties of the nanocapsules were studied. The morphology, chemical composition, microstructure, phase−change characteristics and size distribution of the nanocapsules were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT−IR), transmission electron microscope (TEM), differential scanning calorimeter (DSC) and a zeta potential analyzer. The results confirm that inositol was well−encapsulated by an SiO2 shell. The shell thickness increased, while the supercooling degree of the nanocapsules decreased with increasing time for adding the precursors. In order to obtain nanocapsules with good morphology and phase−change characteristics, the time for adding the precursors should increase with the amount of precursors. The nanocapsules with the best properties exhibited high melting enthalpy, encapsulation ratio and energy storage efficiency of 216.0 kJ/kg, 83.1% and 82.1%, respectively. The size of the nanocapsules was remarkably affected by the triethoxysilane (TES) amount.

scholarly journals Scalability of Phase Change Materials in Nanostructure Template

2015 ◽  
Vol 2015 ◽  
pp. 1-4
Author(s):  
Wei Zhang ◽  
Biyun L. Jackson ◽  
Ke Sun ◽  
Jae Young Lee ◽  
Shyh-Jer Huang ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Scaling Limit ◽  
Phase Change Memory ◽  
Leakage Power ◽  
Memory Element ◽  
Transmission Electron ◽  
Diffraction Mode ◽  
Memory Applications ◽  
Change Memory

The scalability of In2Se3, one of the phase change materials, is investigated. By depositing the material onto a nanopatterned substrate, individual In2Se3nanoclusters are confined in the nanosize pits with well-defined shape and dimension permitting the systematic study of the ultimate scaling limit of its use as a phase change memory element. In2Se3of progressively smaller volume is heated inside a transmission electron microscope operating in diffraction mode. The volume at which the amorphous-crystalline transition can no longer be observed is taken as the ultimate scaling limit, which is approximately 5 nm3for In2Se3. The physics for the existence of scaling limit is discussed. Using phase change memory elements in memory hierarchy is believed to reduce its energy consumption because they consume zero leakage power in memory cells. Therefore, the phase change memory applications are of great importance in terms of energy saving.

Phase-Change Materials/HDPE Composite Filament: A First Step Toward Use With 3D Printing for Thermal Management Applications

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Thomas B. Freeman ◽  
David Spitzer ◽  
Patrick N. Currier ◽  
Virginie Rollin ◽  
Sandra K.S. Boetcher
Keyword(s):  
Thermal Properties ◽  
Electron Microscope ◽  
Phase Change ◽  
Thermal Management ◽  
Latent Heat ◽  
Phase Change Materials ◽  
3D Printer ◽  
Dsc Measurements ◽  
Composite Filament ◽  
Scanning Electron

Phase-change materials (PCMs) are a useful alternative to more traditional methods of thermal management of various applications. PCMs are materials that absorb large amounts of latent heat and undergo solid-to-liquid phase change at near-constant temperature. The goal of the research is to experimentally investigate the thermal properties of a novel shape-stabilized PCM/HDPE composite extruded filament. The extruded filament can then be used in a 3D printer for custom PCM/HDPE shapes. The PCM used in the study is PureTemp PCM 42, which is an organic-based material that melts around 42 °C. Four PCM/HDPE mixtures were investigated (all percentages by mass): 20/80, 30/70, 40/60, and 50/50. Preliminary findings include differential scanning calorimeter (DSC) measurements of melting temperature and latent heat as well as scanning electron microscope (SEM) pictures of filament composition.

scholarly journals Preparation and Experimental Evaluation of Phase-Change Characteristics in Carbon-Based Suspensions

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1315 ◽  
Author(s):  
Tun-Ping Teng ◽  
Ting-Chiang Hsiao ◽  
Chun-Chi Chung
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Phase Change ◽  
Phase Change Materials ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Freezing Temperature ◽  
Combustion Method ◽  
Change Characteristics ◽  
Carbon Based

In this study, micro/nanocarbon-based materials (MNCBMs) were prepared using the high-pressure combustion method (HPCM) with an isoperibol oxygen bomb calorimeter at different oxygen pressures (0.5–3.0 MPa). The prepared MNCBMs were added to water to form carbon-based suspensions (CBSs); sodium dodecyl benzene sulfonate (SDBS) and defoamer were added to the CBSs to enhance their stability. The thermal conductivity, viscosity, density, and contact angle of the CBSs were measured using appropriate instruments to determine their fundamental characteristics. The phase-change characteristics of the CBSs were measured and analyzed using a differential scanning calorimeter (DSC) to evaluate the feasibility of employing them as phase-change materials in ice-storage air-conditioning systems. The results revealed that the maximal change ratios of thermal conductivity, viscosity, density, and contact angle of the samples were −3.15%, 6.25%, 0.23%, and −57.03%, respectively, as compared with the water. The CBS of S5 (oxygen pressure of 2.0 MPa) had the lowest melting temperature and subcooling degree (SD) and the highest freezing temperature in the experiments conducted using the DSC; thus, S5 was determined to be the most suitable CBS for use as a phase-change material of cold energy storage in this study.

Observation of Ge2Sb2Te5 thin film phase transition behavior according to the number of cycles using Transmission Electron Microscope and Scanning Probe Microscope

2006 ◽  
Vol 961 ◽  
Author(s):  
Hyunjung Kim ◽  
Sikyung Choi ◽  
Sukhoon Kang ◽  
Kyuhwan Oh ◽  
Soonyong Kweon
Keyword(s):  
Thin Film ◽  
Phase Transition ◽  
Electron Microscope ◽  
Phase Change ◽  
Transmission Electron Microscope ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Phase Transition Behavior ◽  
Transition Behavior ◽  
Transmission Electron

ABSTRACTRecently, the development of information technology (IT) increases the demands of memory devices. Phase change random access memory (PRAM), based on the reversible phase change of the chalcogenide alloy, Ge2Sb2Te5, is widely regarded as a favourite candidate for the next generation memory. Because of PRAM has a simple cell structure with high scalability; it is non-volatile, has a relatively high read/write operation speed (Â50ns). The PRAM operation relies on the fact that chalcogenide-based materials can be reversible switched from an amorphous phase to a crystalline state by an external electrical current. It is important to study the electrical property with set/reset cycles, since film thickness shrinkage occurs with the phase transition.In this work, we fabricated the 100nm amorphous Ge2Sb2Te5 thin film on TiN/Ti/Si substrate using dc-magnetron sputtering. The 50X50§2 isolated Ge2Sb2Te5 cell was lithographed by the lift-off pattern and wet etching. And TiN top electrode was deposited using pattern align process at room temperature after the SiO2 insulator CMP. Phase transition behavior with the set/reset cycle was observed using I-V measurement and transmission electron microscope (TEM) on isolated Ge2Sb2Te5 cell. The set/reset programming was operated using tungsten SPM tip which was fabricated using focused ion beam (FIB) lithography. I-V curve which was observed by the I-V probe clearly showed that the phase transition was occurred by applying the electric field through the I-V probe. The resistivity difference between amorphous and crystal state was more than 102. After the phase transition, it was also demonstrated with transmission electron microscope (TEM) analysis. For the preparation of TEM specimen of the amorphous and crystalline cell, focused ion beam (FIB) lithography was adopted.

scholarly journals Analysis on the Improvement of Thermal Performance of Phase Change Material Ba (OH)2·8H2O

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7761
Author(s):  
Xiaohui Lu ◽  
Xiaoxue Luo ◽  
Shibo Cao ◽  
Changzhen Zou
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Large Scale ◽  
Phase Change Materials ◽  
Graphite Powder ◽  
Stable Phase ◽  
Heat Conducting ◽  
Supercooling Degree ◽  
Change Material

Benefitting from the characteristics of a high latent heat capacity and stable phase change behavior, phase change materials have widely received concerns in the field of thermodynamic management. Ba(OH)2·8H2O is an ideal phase change material (PCM) in the mid-to-low temperature range, but its large-scale application is still limited by severe supercooling during the nucleation process. In this paper, the experimental analysis and comparison are performed via an Edisonian approach, where Ba(OH)2·8H2O is adopted as an original substrate; BaCO3, CaCl2, NaCl, KH2PO4, and NaOH are selected as nucleating agents; and graphite is used as a heat-conducting agent. The results show that Ba(OH)2·8H2O containing 1.2% BaCO3 and 0.2% graphite powder has the best performance. Compared with pure Ba(OH)2·8H2O, the supercooling degree is reduced to less than 1 °C, the phase change latent heat duration is extended, and the thermal conductivity is significantly improved. Therefore, this study not only provides a reference for the application of Ba(OH)2·8H2O, but can also be used as a guidance for other material modifications.

Preparation and Performance of Microencapsulated Phase Change Material with Paraffin Core and SiO2 Shell for High Latent Heat and Low Heat Loss by Sol–Gel Method

NANO ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. 2050156
Author(s):  
Xiaokun Yu ◽  
Jingde Luan ◽  
Wei Chen ◽  
Jialu Tao
Keyword(s):  
Phase Change ◽  
Heat Loss ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Sio2 Shell ◽  
Key Factor ◽  
And Performance

Microencapsulated phase change materials (MicroPCM) were prepared via sol–gel method using paraffin as heat storage core and silica as inorganic shell. The morphology feature, chemical structure, thermal properties and thermal stability of MicroPCM were characterized by the field emission scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FTIR), the differential scanning calorimeter (DSC), simultaneous thermal analyzer (STA) and the thermal conductivity meter. The results indicated that MicroPCM were spherical in shape with the shell thickness in the range from 236[Formula: see text]nm to 303[Formula: see text]nm. The stirring speed and TEOS dosage were key factor on the latent heat and supercool effect of MicroPCM. The maximum latent heat of MicroPCM was 240.2[Formula: see text][Formula: see text] with the heat loss of only 0.2[Formula: see text][Formula: see text] in phase transformation when it was prepared at the stirring speed of 400[Formula: see text]r/min and TEOS dosage of 20[Formula: see text]ml. MicroPCM was a promising material for thermal energy storage (TES).

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