Use of Minimal Free Energy and Self-Assembly To Form Shapes

1995 ◽  
Vol 7 (6) ◽  
pp. 1257-1264 ◽  
Author(s):  
Enoch Kim ◽  
George M. Whitesides
Keyword(s):  
Free Energy ◽  
Self Assembly ◽  
Minimal Free Energy

B4/32Ga28/32Sb10/32As22/32 Three-Dimensional Semiconductor Superlattice

2021 ◽  
Author(s):  
Viacheslav Elyukhin ◽  
Ramon Peña Sierra
Keyword(s):  
Free Energy ◽  
Self Assembly ◽  
Strain Energy ◽  
Three Dimensional ◽  
Semiconductor Alloys ◽  
X Ray Diffraction ◽  
Minimal Free Energy ◽  
X Ray ◽  
Semiconductor Superlattice ◽  
Semiconductor Alloy

Abstract Self-assembly of BD -rich A x B 1-x C y D 1-y was studied for a lot of semiconductor alloys. An occurrence of identical clustersshould be due to a decrease of the bond energy, internal strain energy or both of them. An arrangement of the clusters is disordered since the contents of minority atoms are in the dilute or ultra dilute limits in the considered alloys. B 4/32 Ga 28/32 Sb 10/32 As 22/32 semiconductor alloy with the three-dimensional superlattice is presented. This superlattice should be stable against disordering due to its minimal free energy. The superlattice forms by the identical cubic units consisting of 64 atoms and is the three-dimensional semiconductor soft X-ray diffraction grating.

scholarly journals Surface modification and adhesion improvement of polyester films

2013 ◽  
Vol 11 (1) ◽  
pp. 35-45 ◽  
Author(s):  
Aniello Cammarano ◽  
Giovanna Luca ◽  
Eugenio Amendola
Keyword(s):  
Free Energy ◽  
Surface Modification ◽  
Surface Free Energy ◽  
Self Assembly ◽  
Treatment Time ◽  
Solution Treatment ◽  
Film Surface ◽  
Critical Surface ◽  
Hydrolysis Time ◽  
Critical Surface Tension

AbstractFacile surface modification of polyester films was performed via chemical solutions treatment. Surface hydrolysis was carried out by means of sodium hydroxide solutions, leading to the formation of carboxylate groups. Three commercial polyester films of 100 μm in thickness were used in this work: AryLite™, Mylar™, and Teonex™, hydrolysis time being the main modification parameter. FTIR-ATR analysis, topography and contact angle (CA) measurements, surface free energy (SFE) and T-Peel adhesion tests were carried out to characterize the modified films. A quantitative estimate of the carboxylates surface coverage as a function of treatment time was obtained through a supramolecular approach, i.e. the ionic self-assembly of a tetracationic porphyrin chromophore onto the film surface. The surface free energy and critical surface tension of the hydrolyzed polyesters was evaluated by means of Zisman, Saito, Berthelot and Owens-Wendt methods. It was shown that NaOH solution treatment increases roughness, polarity and surface free energy of polymers. As a result, T-Peel strengths for modified Mylar™ and Teonex™ films were respectively 2.2 and 1.8 times higher than that for the unmodified films, whereas AryLite™ adhesion test failed.

scholarly journals Two-step crystallization and solid–solid transitions in binary colloidal mixtures

2020 ◽  
Vol 117 (45) ◽  
pp. 27927-27933
Author(s):  
Huang Fang ◽  
Michael F. Hagan ◽  
W. Benjamin Rogers
Keyword(s):  
Free Energy ◽  
Self Assembly ◽  
Materials Science ◽  
Protein Structures ◽  
Free Energy Barrier ◽  
Enhanced Sampling ◽  
Homogeneous Fluid ◽  
Metastable Structures ◽  
One Step ◽  
Crystal Phases

Crystallization is fundamental to materials science and is central to a variety of applications, ranging from the fabrication of silicon wafers for microelectronics to the determination of protein structures. The basic picture is that a crystal nucleates from a homogeneous fluid by a spontaneous fluctuation that kicks the system over a single free-energy barrier. However, it is becoming apparent that nucleation is often more complicated than this simple picture and, instead, can proceed via multiple transformations of metastable structures along the pathway to the thermodynamic minimum. In this article, we observe, characterize, and model crystallization pathways using DNA-coated colloids. We use optical microscopy to investigate the crystallization of a binary colloidal mixture with single-particle resolution. We observe classical one-step pathways and nonclassical two-step pathways that proceed via a solid–solid transformation of a crystal intermediate. We also use enhanced sampling to compute the free-energy landscapes corresponding to our experiments and show that both one- and two-step pathways are driven by thermodynamics alone. Specifically, the two-step solid–solid transition is governed by a competition between two different crystal phases with free energies that depend on the crystal size. These results extend our understanding of available pathways to crystallization, by showing that size-dependent thermodynamic forces can produce pathways with multiple crystal phases that interconvert without free-energy barriers and could provide approaches to controlling the self-assembly of materials made from colloids.

Static Torsion of a Magnetostrictive Bimorph with In-Plane Anisotropy

2009 ◽  
Vol 60-61 ◽  
pp. 410-415
Author(s):  
Bai Narsu ◽  
Guo Hong Yun
Keyword(s):  
Free Energy ◽  
External Field ◽  
Magnetic Anisotropy ◽  
Cantilever Beam ◽  
Experimental Result ◽  
Minimal Free Energy ◽  
Plane Anisotropy ◽  
Flexion Response ◽  
Twisting Deformation ◽  
Static Torsion

A model for the bending and twisting deformation of the giant magnetostrictive cantilever is established in the framework of the principle of minimal free energy and four-parameter bending regime. The angular and magnitude dependence of the torsion and flexion response on the external field was discussed for cantilever beam. The torsion behavior of the cantilever is very sensitive to the external field and shows a hysteresis. Furthermore, the torsion hysteresis of the cantilever calculated by our model qualitatively agrees with recent experimental result, which suggests that our model is effective in describing the cantilever system with magnetic anisotropy.

Densification and fine grain formation mechanisms of BaTiO3 ceramics consolidated by self-assembly sintering

2021 ◽  
Author(s):  
Quan Jin ◽  
Lili Zhao ◽  
Xiaoting Zhang ◽  
Run Zhang ◽  
Bin Cui
Keyword(s):  
Particle Size ◽  
Free Energy ◽  
Grain Growth ◽  
Surface Free Energy ◽  
Self Assembly ◽  
Formation Mechanisms ◽  
Fine Grained ◽  
Fine Grain ◽  
Angle Method ◽  
Sintering Method

Abstract In this paper, from the perspective of thermodynamics and kinetics, we have studied the mechanism of balancing the densification and grain growth via co-sintering the micron and nano powders, also known as self-assembly sintering. In the experiment, the 200 nm and 80 nm BaTiO 3 spherical powders were used as models for combination and co-sintering. In terms of thermodynamics, the contact angle method is applied to determine the free energy of the binary particle size system. The surface free energy of 200 nm and 80 nm BaTiO 3 powders are 51.66 J/mol and 203.47 J/mol, respectively. When the powder ratio is 1:1, the surface free energy of the binary particle size system is 127.56 J/mol, which is the reason for the balance between densification and grain growth. In terms of kinetics, the Arrhenius equation was utilized to calculate the apparent activation energy ( Q ) of the binary particle size system. The results show that the value of Q is 360 kJ/mol at 1000 °C. The fine-grained ceramics with high relative density obtained by this sintering method at a low sintering temperature (1000 °C) can be explained by the relative low value of Q.

scholarly journals Knowing one's place: a free-energy approach to pattern regulation

2015 ◽  
Vol 12 (105) ◽  
pp. 20141383 ◽  
Author(s):  
Karl Friston ◽  
Michael Levin ◽  
Biswa Sengupta ◽  
Giovanni Pezzulo
Keyword(s):  
Free Energy ◽  
Self Assembly ◽  
Theoretical Formulation ◽  
Genetic Codes ◽  
Variational Free Energy ◽  
Action And Perception ◽  
Cell Groups ◽  
Biological Pattern Formation ◽  
Pattern Regulation ◽  
Epigenetic Processes

Understanding how organisms establish their form during embryogenesis and regeneration represents a major knowledge gap in biological pattern formation. It has been recently suggested that morphogenesis could be understood in terms of cellular information processing and the ability of cell groups to model shape. Here, we offer a proof of principle that self-assembly is an emergent property of cells that share a common (genetic and epigenetic) model of organismal form. This behaviour is formulated in terms of variational free-energy minimization—of the sort that has been used to explain action and perception in neuroscience. In brief, casting the minimization of thermodynamic free energy in terms of variational free energy allows one to interpret (the dynamics of) a system as inferring the causes of its inputs—and acting to resolve uncertainty about those causes. This novel perspective on the coordination of migration and differentiation of cells suggests an interpretation of genetic codes as parametrizing a generative model—predicting the signals sensed by cells in the target morphology—and epigenetic processes as the subsequent inversion of that model. This theoretical formulation may complement bottom-up strategies—that currently focus on molecular pathways—with (constructivist) top-down approaches that have proved themselves in neuroscience and cybernetics.

Self-assembly of bioelastomeric structures from solutions: Mean-field critical behavior and Flory-Huggins free energy of interactions

Biopolymers ◽  
1993 ◽  
Vol 33 (5) ◽  
pp. 743-752 ◽  
Author(s):  
F. Sciortino ◽  
K. U. Prasad ◽  
D. W. Urry ◽  
M. U. Palma
Keyword(s):  
Free Energy ◽  
Critical Behavior ◽  
Self Assembly ◽  
Mean Field

scholarly journals Effects of co-ordination number on the nucleation behaviour in many-component self-assembly

2016 ◽  
Vol 186 ◽  
pp. 215-228 ◽  
Author(s):  
Aleks Reinhardt ◽  
Chon Pan Ho ◽  
Daan Frenkel
Keyword(s):  
Free Energy ◽  
Self Assembly ◽  
Driving Force ◽  
Building Blocks ◽  
The Self ◽  
Energy Barriers ◽  
Distinct Component ◽  
Lattice Monte Carlo ◽  
High Supersaturation ◽  
Grand Canonical

We report canonical and grand-canonical lattice Monte Carlo simulations of the self-assembly of addressable structures comprising hundreds of distinct component types. The nucleation behaviour, in the form of free-energy barriers to nucleation, changes significantly as the co-ordination number of the building blocks is changed from 4 to 8 to 12. Unlike tetrahedral structures – which roughly correspond to DNA bricks that have been studied in experiments – the shapes of the free-energy barriers of higher co-ordination structures depend strongly on the supersaturation, and such structures require a very significant driving force for structure growth before nucleation becomes thermally accessible. Although growth at high supersaturation results in more defects during self-assembly, we show that high co-ordination number structures can still be assembled successfully in computer simulations and that they exhibit self-assembly behaviour analogous to DNA bricks. In particular, the self-assembly remains modular, enabling in principle a wide variety of nanostructures to be assembled, with a greater spatial resolution than is possible in low co-ordination structures.

Sign in / Sign up

Export Citation Format

Share Document