Special Issue "Programmable Anisotropic Materials and Composites"
A special issue of Materials (ISSN 1996-1944).
Deadline for manuscript submissions: 31 December 2019
Programmable anisotropic materials and composites are attractive because of their directed material properties, including mechanical, thermal, electrical, magnetic, and optical properties. Recently, programmable anisotropic materials have also offered the opportunity to study soft robotics, self-assembly, and shape-reconfigurable materials and devices.
The purpose of this Special Issue is to collect high-quality articles in the field of liquid crystalline materials, magnetic composites, as well as novel anisotropic materials programmed by various external stimuli including electrical fields, temperature gradient, spatial confinement, capillary force, and shear force.
It is my pleasure to invite you to submit a manuscript for this Special Issue. Full papers, communications, and reviews are all welcome.
Prof. Dr. Jeong Jae Wie
Manuscript Submission Information
Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.
Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.
Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.
- liquid crystalline materials
- magnetic composites
- programmable materials
- stimuli-responsive materials
- anisotropic materials
- soft robotics
- shape-reconfigurable materials
The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.
1. Title: Virus-like Particles as Self-Assembly, Anisotropic, Shape-reconfigurable Materials
Authors: Mariana Andrade-Medina and Mauricio Carrillo-Tripp
Abstract: A virus is a biological complex formed by an infecting genome inside an outer protein shell called capsid. In many cases, it is possible to form empty capsids in vitro. Such particles, referred to as virus-like particles or VLPs, are monodispersed and retain the nanoscale size and shape of the original virus particle. VLPs have remarkable geometric and physicochemical features. Under the right conditions, they reversibly self-assemble. Changes in pH or salt concentration can reconfigure their shape. Furthermore, VLPs show anisotropic behaviors even though they have symmetrical structures. Here, we will examine a range of applications and implications of VLP-based nanomaterials, focusing on exciting new advancements in their rational design.
2. Title: Properties of dislocation drag from phonon wind at ambient conditions
Author: Daniel N. Blaschke
Abstract: It is well known that under plastic deformation, dislocations are not only created but also move through the crystal, and their mobility is impeded by their interaction with the crystal structure. At high stress and temperature, this "drag" is dominated by phonon wind, i.e. the scattering off phonons. Employing the semi-isotropic approach discussed in detail in [J. Phys. Chem. Solids 124 (2019) 24], we discuss here the approximate functional dependence on dislocation velocity in various regimes between a few percent of transverse sound speed c_t and c_t (where c_t is the effective average transverse sound speed of the
polycrystal). In doing so, we find an effective functional form for dislocation drag B(v) for different slip systems and dislocation characters at fixed (room) temperature and low pressure.
3. Title: Hierarchically Ordered Nanostructures on a Chemically Defined Surface via Flow-Enabled Self-Assembly
Authors: Ha Ryeong Cho; Woon-Ik Park; Myunghwan Byun
Abstract: By capitalizing on two consecutive self-assembly processes at different length scales, hierarchically ordered structures composed of diblock copolymers on gradient chemically patterned surface were crafted. A chemically modified surface at micrometer scale was first fabricated by flow-enabled self-assembly of polymer lines, followed by the physical detachment of weakly deposited polymer, resulting in physically adsorbed polymer stripes on the Si substrate [1-2]. Subsequently, asymmentric diblock copolymer, poly(styrene-b-dimethylsiloxane) (PS-b-PDMS), was spin-coated and treated with solvent vapor for unfavorable interfacial interaction-driven destabilization of diblock copolymer thin film and simulataneous microphase separation of immiscible blocks, thus giving highly ordered nanocylinders in spatially defined surface at micrometer scale. Selection of PS-b-PDMS as the target diblock copolymer was strongly motivated with easy organic-inorganic trasfromation of nanostructures through plasma treatment . The entire experimental results were carefully analyzed using optical microscopy (OM), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Notably, ultrathin, chemically defined polymer stripes were well-prepared in a simple, unconventional, and remarkably controllable manner at low cost, dispensing with the need for costly and multistep lithography techniques. These hierarchically ordered structures may offer as a promising template for the potential applications such as optics, electronics, optoelectronics with tunable functionalities, and desirable spatial arrangement.
4. Title: Research of 80% fly-ash content concrete applied in hydraulic engineering based on the anisotropic thermo-chemo-mechanical model
Authors: Tianqi Qi, Xiaolin Chang, Wei Zhou, Wenxiang Tian, Gang Ma
Abstract: Increasing the amount of fly ash which is characterized of pozzolanic reactivity in concrete is an effective and reliable way to solve the problems of high hydration heat and high shrinkage. The concrete samples with 35% and 80% fly-ash content are prepared by the method of keeping the cement volume basically unchanged, and all the concrete properties meet the requirements of the hydraulic concrete. According to the thermodynamic test data, the hydration characteristics of fly-ash concrete were studied, and the relationship between thermal expansion coefficient and hydration degree is established. The optimized thermo-chemo-mechanical (TCM) model is adopted to simulate the evolution of the macroscopic properties of fly-ash concrete, and the calculated results are in agreement with the experimental one. In reality concrete is a mixture of sands and gravels and it is an anisotropic material. Therefore, after verifying the accuracy of the macro-model, an anisotropic model on the meso-scale is established to reflect the non-uniformity of concrete. The anisotropy of thermal deformation of concrete is also studied on this basis.
5. Title: A new computerized nonlinear boundary element modeling and simulation of three-temperature generalized micropolar-thermoelasticity with memory-dependent derivatives in anisotropic smart structures
Author: Mohamed Abdelsabour Fahmy
Abstract: The main aim of this article is to introduce a new memory-dependent derivatives theory to contribute for increasing development of technological and industrial applications of anisotropic materials. This theory, called three-temperature nonlinear anisotropic generalized micropolar-thermoelasticity theory. The governing equations of this theory are very difficult to solve analytically because of nonlinearity. So, we need to develop new numerical techniques for solving such equations. Therefore, we propose a new boundary element formulation for solving the theory’s governing equations. The numerical results are presented highlighting the effects of the kernel function and time delay on the temperatures and displacements. The numerical results also demonstrate the validity, efficiency and accuracy of the proposed technique. It can be concluded from numerical results of our current complex and general study that Some well-known anisotropic micropolar thermoelasticity theories such as anisotropic micropolar porothermoelasticity, anisotropic micropolar magneto-thermoelasticity, anisotropic micropolar viscothermoelasticity and anisotropic micropolar piezothermoelasticity can be combined with the three-temperature radiative heat conduction to describe the deformation of anisotropic smart structures in the context of memory-dependent derivatives of these important anisotropic micropolar thermoelastic theories.
6. Title: Characteristics of ternary Portland cement and numerical simulation based on the thermo-mechanical-chemical coupling model
Authors: Wei Zhou, Wenxiang Tian, Xiaolin Chang, Tianqi Qi, Shuhua Liu, Chuqiao Feng and Gang Ma
Abstract: Ternary complex cement-based material is a popular way of improving the properties of concrete. In this work, we performed a series of laboratory tests and numerical simulations on ternary Portland cement containing different ratios of limestone-powder and fly-ash. The mechanical properties, such as uniaxial compressive strength and hydration heat were measured. The hydration products and pore structure were characterized by mercury intrusion porosimetry (MIP), scanning electron microscope (SEM) and X-ray diffraction (XRD). Based on the test results, the ternary cementitious materials were simulated using the thermo-mechanical-chemical coupling model and the random pore model, which can reflect the thermal and mechanical anisotropy properties of the mixed mortar caused by sands and pores. The experiment and numerical simulation results both suggest the optimum ratio of limestone-powder to fly-ash (30%/20%, the total admixture content is 50%) can enhance the strength of early-age concrete without sacrificing the long-term strength. The multi-physical coupling model can reproduce the “Hump type” hydration acceleration stage, which is caused by limestone-powder. Besides, the limestone powder can significantly reduce porosity, and reduce the anisotropy of matrix especially in the interfacial transition zone (ITZ), which is verified by the MIP results and simulations.
7. Title: Electrical Switching between Reflective and Transparent States in Polymer Stabilized Cholesteric Liquid Crystals
Authors: Kyung Min Lee, Timothy J. White, Timothy J. Bunning, and Michael E. McConney
We report on a unique color switching in polymer stabilized cholesteric liquid crystals (PSCLCs) with negative dielectric anisotropy. The electrical switching is enabled in these thin PSCLC samples through a DC-field induced pitch variation across the liquid crystal cell. At lower DC-fields a relatively small non-linear pitch variation across the thickness of the cell shifts the PSCLC reflection to longer wavelengths. At higher DC voltages a strong non-linearity in the cholesteric liquid crystal pitch and the spectral reflection disappears and becomes transparent. This transparency is created by the combination of a strongly chirped pitch and relatively small thickness of the cells, which creates a PSCLC with such a strong variation in pitch that there is no spectral reflection pitches associated with any wavelength to lead to reflection. By adjusting the DC field strength, different colored reflections can be addressed. The switching behavior of the PSCLC can be potentially used in display applications.