scholarly journals Thermal and Mechanical Stabilities of Core-shell Microparticles Containing a Liquid Core

Author(s):  
Nam-Trung Nguyen ◽  
Nam-Trung Nguyen ◽  
Nam-Trung Nguyen ◽  
Nam-Trung Nguyen

Abstract Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.

2021 ◽  
Author(s):  
Fariba Malekpour Galogahi ◽  
Hongjie An ◽  
Yong Zhu ◽  
Nam-Trung Nguyen

Abstract Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.


Langmuir ◽  
2014 ◽  
Vol 30 (47) ◽  
pp. 14308-14313 ◽  
Author(s):  
Ian D. Tevis ◽  
Lucas B. Newcomb ◽  
Martin Thuo

2021 ◽  
Vol 17 (3) ◽  
pp. 439-446
Author(s):  
Hongjun Xia ◽  
Huaiming Wang ◽  
Jianshan Wang ◽  
Lin Wang ◽  
Lin Jin ◽  
...  

As it is difficult to prevent secondary nucleation and agglomeration during the preparation of core–shell silica microspheres, these issues have been successfully resolved in this study using template-dissolution-induced redeposition. The non-porous particles are transformed into core–shell silica microspheres (CSSMs) in the presence of cetyltrimethylammonium bromide and octyltrimethylammonium bromide under basic conditions. The shell thickness and pore sizes of the CSSMs are controlled by adjusting the etching time and molar ratio of the template, respectively. The CSSMs are modified using octadecyltrimethylammonium chloride to separate the mixture of alkyl benzenes, and a high column separation efficiency is achieved within two minutes. The CSSMs are used for the separation and analysis of proteins and the digests of bovine serum albumin. The chromatographic column packed with core–shell particles affords a significantly higher separation efficiency than the commercial column. Therefore, as a chromatographic stationary phase, these core–shell particles can potentially be used for the fast separation of proteins, small solutes, and complex samples.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Simge Çınar ◽  
Ian D. Tevis ◽  
Jiahao Chen ◽  
Martin Thuo

Abstract Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate (‘/’ = physisorbed, ‘-’ = chemisorbed), from molten Field’s metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.


2021 ◽  
Author(s):  
Fariba Malekpour Galogahi ◽  
Yong Zhu ◽  
Hongjie An ◽  
Nam-Trung Nguyen

Abstract Accurate control of monodisperse core-shell droplets generated in a microfluidic device has a broad range of applications in research and industry. This paper reports the experimental investigation of flow-focusing microfluidic devices capable of producing size-tuneable and monodisperse core-shell droplets. The dimension of the core-shell droplets was controlled passively by the channel geometry and the flow rate of the liquid phases. The results indicate that microchannel geometry is more significant than flow rates. The highly controllable core-shell droplets could be subsequently employed as a template for generating core-shell micropaticles with liquid core. Optical, electron microscopy and X-ray computed microtomography showed that the geometry of the core-shell droplets remains unchanged after solidification, drying and collection. The present study also looks at the thermal stability of core-shell particles depending on the particle size. The larger core-shell partcles with a thicker shell provide a higher resistance to heating at elevated temperature. The high degree of control with a flow-focusing microfluidic device makes this a promising approach for the encapsulation, storage, and delivery of lipophilic contents.


2006 ◽  
Vol 988 ◽  
Author(s):  
Yi-Yeoun Kim ◽  
John W Catino ◽  
Gary P Tomaino ◽  
Sherman D Cox

AbstractIn this report, we present a bio-inspired encapsulation process to create nanocluster-assembled core-shell particles under aqueous, room temperature and non-toxic conditions. The approach to synthesize calcium carbonate core-shell particles is accomplished by employing a Polymer-Induced Liquid-Precursor (PILP) process. We demonstrate the amorphous mineral precursor is coated around a core of hydrogel nanoparticles, and subsequently solidified and crystallized. The synthesized core-shell particles are 300∼500nm diameter and ∼100 nm shell-thickness. We investigate the role of the hydrogel core of the particle using time-resolved XRD, thermal-XRD and thermal analysis. The organic hydrogel appears to influence the transformation of mineral phases, stabilizing the amorphous phase of calcium carbonate.


2015 ◽  
Vol 11 (6) ◽  
pp. 1021-1027 ◽  
Author(s):  
Xia Xu ◽  
Yang-Ki Hong ◽  
Jihoon Park ◽  
Woncheol Lee ◽  
Alan M. Lane

2012 ◽  
Vol 45 (3) ◽  
pp. 513-516 ◽  
Author(s):  
Joachim Wagner

The scattering function for polydisperse core–shell particles with Schulz–Flory size distributions of both the core radius and the shell thickness is analytically calculated. The results of the analytical solution are compared with the results of a numerical integration over both size distributions, as well as with available analytical solutions for homogeneous spheres. The CPU time required for the calculation of the scattering function can be reduced by several orders of magnitude compared with numerical integration. This is of tremendous importance in nonlinear curve fitting requiring repeated calculation of the theoretical function in an iterative process.


2019 ◽  
Vol 27 (11) ◽  
pp. 1104-1109 ◽  
Author(s):  
Jun Young Kim ◽  
Sung Ho Choi ◽  
Ji Hun An ◽  
Seong Jae Lee

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