Control Of Domain Size Research Articles

Domain size control by spinodal decomposition in ferroelectrics

Just as fine precipitate dispersions are sought for high yield strength in alloys, nanoscale, mixed-phase microstructures are sought for high electromechanical performance in oxide ferroelectric materials. Spinodal decomposition is an effective route to fine-scale alloy microstructures and is exploited commercially, for example, in bronzes. Spinodal decomposition has been linked to nanoscale ferroelectric microstructures, but a comprehensive analysis is missing. Here spinodal decomposition in ferroelectric crystals is analysed in 3D including the local electric field using the ferroelectric multi-phase field model for polymorphic phase boundary (PPB) systems. A polarisation consulate temperature Tsp is identified: in single phase ferroelectric, Tsp=Tcw, and, in PPB ferroelectrics, Tcw,ζ=0<Tsp<Tcw,ζ=1. The stability of fluctuations in polarisation depends on temperature, is isotropic in wavevector k→, and corresponds to 2D waves in ceramics. General predictions are summarised and specific predictions for single phase and a PPB system (1−x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) are made. At 284K, the minimum wavelength is lcritBT=166nm in BaTiO3 and lcritPZT=1.70nm in Pb(Zr,Ti)O3, suggesting that spinodal decomposition is less likely to be observed in BaTiO3. For BZT-40BCT, the minimum observable wavelength at TPPB is ∼22 unit cells lcritBZT−40BCT=8.72nm and presents a viable route to nanoscale rhombohedral + tetragonal microstructures. Domain size engineering by spinodal decomposition with controlled grain structures and quenching in oxide and organic ferroelectrics is identified as a new route to optimise performance.

The experiment and simulation of enhanced mechanical performance for polyethylene terephthalate/high‐density polyethylene composites via domain size control

AbstractSolid‐state shear milling (S3M) equipment is proficient for achieving room‐temperature ultrafine grinding of multicomponent polymers, demonstrating significant potential in polymer blending and waste plastic recycling. However, a systematic investigation of S3M's ability to control the domain size of multicomponent polymer is currently lacking, which was of great potential for the high‐value recycling of waste plastics that are difficult to separate and thermodynamically incompatible. As the raw material of beverage bottle, polyethylene terephthalate/high‐density polyethylene (PET/HDPE) system with tremendous production was hard to be recycled together. Therefore, in this study, we chose PET/HDPE for the study of domain size control efficiency of S3M on mechanical properties of polymer blend. We also measured the processing parameters during the fabrication of PET/HDPE blended powder to determine the optimal manufacturing parameters for the polymer composite with outstanding mechanical property. After 30 milling cycles, the powder size of PET/HDPE gradually decreased from 849.8 μm (2 cycles) to 43.2 μm, which related to PET domain size of 71.9 and 5.2 μm, respectively. Meanwhile, at 24 milling cycles, the PET/HDPE composites reached the highest tensile strength of 27.6 MPa, meeting the most proper milling condition for PET/HDPE system. Finite element computer simulation was introduced to further investigate the domain size influence on mechanical property of PET/HDPE composites, which acquired similar results with the experimental value before excessive milling cycles. Based on both the experimental results and simulation support, a theoretical basis for the domain‐size‐control analysis of S3M in multicomponent waste polymer recycling was established.

Domain size control in all-polymer solar cells

SummaryIn all polymer solar cells (all-PSCs), the domain size is critical for device performance. In highly crystalline polymer blends, however, precisely adjusting the domain size remains a significant challenge because of the simultaneous crystallization of both components. Herein, a strategy that promotes acceptor and donor to crystallize separately was proposed. Take PBDB-T/N2200 blends for instance; the solution state and confined crystallization were combined, which induced the crystallization of N2200, and PBDB-T occurred during the film-forming process and at thermal annealing stage. This separated crystallization process lowers the driving force of phase separation without affecting the degree of crystallinity of the blends. Thus, an interpenetrating network with high crystallinity and proper domain size was obtained, which boosted the power conversion efficiency to 7.59%. Importantly, the relation between pre-aggregation and domain size was established, which may be a guide to precisely adjust the active layer’s domain size in all-PSCs.

A picket fence function for adherens junctions in epithelial cell polarity.

Adherens junctions are a defining feature of all epithelial cells, providing cell-cell adhesion and contractile ring formation that is essential for cell and tissue morphology. In Drosophila, adherens junctions are concentrated between the apical and basolateral plasma membrane domains, defined by aPKC-Par6-Baz and Lgl/Dlg/Scrib, respectively. Whether adherens junctions contribute to apical-basal polarization itself has been unclear because neuroblasts exhibit apical-basal polarization of aPKC-Par6-Baz and Lgl in the absence of adherens junctions. Here we show that, upon disruption of adherens junctions in epithelial cells, apical polarity determinants such as aPKC can still segregate from basolateral Lgl, but lose their sharp boundaries and also overlap with Dlg and Scrib - similar to neuroblasts. In addition, control of apical versus basolateral domain size is lost, along with control of cell shape, in the absence of adherens junctions. Manipulating the levels of apical Par3/Baz or basolateral Lgl polarity determinants in experiments and in computer simulations confirms that adherens junctions provide a 'picket fence' diffusion barrier that restricts the spread of polarity determinants along the membrane to enable precise domain size control. Movement of adherens junctions in response to mechanical forces during morphogenetic change thus enables spontaneous adjustment of apical versus basolateral domain size as an emergent property of the polarising system.

The mechanism of side reaction induced capacity fading of Ni-rich cathode materials for lithium ion batteries

Optimized domain size endows Ni-rich cathode with both sufficient electrolyte infiltration and modest side reaction. Surface structure degradation caused by HF erosion is the main reason of the capacity fading, rather than LiF deposition. • The domain size of Ni-rich cathode influences the side reaction with electrolyte. • LiF deposition from side reaction shows little impact on cycling stability. • HF erosion caused surface phase transition is the main reason for capacity fading. Ni-rich cathode materials show great potential of applying in high-energy lithium ion batteries, but their inferior cycling stability hinders this process. Study on the electrode/electrolyte interfacial reaction is indispensable to understand the capacity failure mechanism of Ni-rich cathode materials and further address this issue. This work demonstrates the domain size effects on interfacial side reactions firstly, and further analyzes the inherent mechanism of side reaction induced capacity decay through comparing the interfacial behaviors before and after MgO coating. It has been determined that LiF deposition caused thicker SEI films may not increase the surface film resistance, while HF erosion induced surface phase transition will increase the charge transfer resistance, and the later plays the dominant factor to declined capacity of Ni-rich cathode materials. This work suggests strategies to suppress the capacity decay of layered cathode materials and provides a guidance for the domain size control to match the various applications under different current rates.

Correction to High-Quality Dual-Plasmonic Au@Cu2–xSe Nanocrescents with Precise Cu2–xSe Domain Size Control and Tunable Optical Properties in the Second Near-Infrared Biowindow

Correction to High-Quality Dual-Plasmonic Au@Cu_2–<i>x</i>Se Nanocrescents with Precise Cu_2–<i>x</i>Se Domain Size Control and Tunable Optical Properties in the Second Near-Infrared Biowindow

Ordered Nanoporous Carbons with Broadly Tunable Pore Size Using Bottlebrush Block Copolymer Templates.

We report the preparation of ordered porous carbon materials with tailored pore sizes selected between 16 and 108 nm using bottlebrush block copolymers (BBCPs) as templates. The nanoporous carbons are prepared via the cooperative assembly of polydimethylsiloxane-block-poly(ethylene oxide) (PDMS-b-PEO) BBCPs with phenol-formaldehyde resin yielding ordered precursor films, followed by carbonization. The assembly of PDMS-b-PEO BBCPs with the resin leads to films exhibiting a spherical morphology (PDMS as the minor domain) with uniform domain sizes between 18 and 150 nm in the bulk. The assembled PDMS sphere diameters scale linearly with BBCPs molecular weights, allowing precise control of domain size. Access to very large ordered domains is an enabling hallmark of BBCPs self-assembly, but reports of well-ordered spherical domains are not common. Carbonization of the ordered precursor films yields nanoporous carbon with uniform and tunable pore size. These nanoporous carbons are shown to exhibit excellent performance as supercapacitor electrodes with capacitance reaching up to 254 F g-1 at a current density of 2 A g-1.

Spontaneous wettability patterning via creasing instability

Surfaces with patterned wettability contrast are important in industrial applications such as heat transfer, water collection, and particle separation. Traditional methods of fabricating such surfaces rely on microfabrication technologies, which are only applicable to certain substrates and are difficult to scale up and implement on curved surfaces. By taking advantage of a mechanical instability on a polyurethane elastomer film, we show that wettability patterns on both flat and curved surfaces can be generated spontaneously via a simple dip coating process. Variations in dipping time, sample prestress, and chemical treatment enable independent control of domain size (from about 100 to 500 μm), morphology, and wettability contrast, respectively. We characterize the wettability contrast using local surface energy measurements via the sessile droplet technique and tensiometry.

Phase separation, crystallinity and monomer-aggregate population control in solution processed small molecule solar cells

Small conjugated molecules are of great interest as promising alternatives to semiconducting polymers in organic photovoltaics (OPV). In this work, we introduce a more accurate assignment of the excited state of a promising squaraine (SQ) targeted for OPV application. From this assignment, we conclude that a mixed population of monomers and aggregates exists in spin-cast SQ:PC61BM bulk heterojunction (BHJ) films, where monomers indicate the presence of amorphous regions that could act as traps. Since crystallinity is critically important for efficient charge transport and exciton diffusion in the BHJ, we thermally anneal the as-cast films to reduce the amorphous regions. Our analysis of annealed films demonstrates a delicate trade-off between increased crystallinity and larger domain sizes. Crystallinity improves but often at the expense of larger crystal size, as supported by XRD and TEM study. Therefore, to achieve optimal OPV efficiency, we controlled the tradeoff to improve the crystallinity while maintaining a small, highly mixed BHJ morphology. We thus highlight the importance of chemical compatibility when designing small molecules for use in high efficiency BHJ devices. Significantly, we have connected theoretically validated spectroscopic assignment with the first full study of morphology and domain size control as they affect small molecule OPV active layers.

Charged particle-induced synthesis of carbon nanowalls and characterization

High deposition rate, control of domain size, detailed characterization and charged particle-induced growth mechanism of CNW films are reported.

Transient domain formation in membrane-bound organelles undergoing maturation

The membrane components of cellular organelles have been shown to segregate into domains as the result of biochemical maturation. We propose that the dynamical competition between maturation and lateral segregation of membrane components regulates domain formation. We study a two-component fluid membrane in which enzymatic reaction irreversibly converts one component into another and phase separation triggers the formation of transient membrane domains. The maximum domain size is shown to depend on the maturation rate as a power law similar to the one observed for domain growth with time in the absence of maturation, despite this time dependence not being verified in the case of irreversible maturation. This control of domain size by enzymatic activity could play a critical role in regulating exchange between organelles or within compartmentalized organelles such as the Golgi apparatus.

2G1436 人工細胞ベシクルにおける脂質ドメインへの化合物局在を介したドメインサイズと膜崩壊率の制御(生体膜・人工膜,口頭発表,日本生物物理学会第50回年会(2012年度))

2G1436 人工細胞ベシクルにおける脂質ドメインへの化合物局在を介したドメインサイズと膜崩壊率の制御(生体膜・人工膜,口頭発表,日本生物物理学会第50回年会(2012年度))

Control of domain configurations and sizes in crystallographically engineered ferroelectric single crystals: Phase field modeling

Computer simulation is performed to study the mechanisms for controlling domain configurations and sizes in crystallographically engineered ferroelectric crystals. It is found that minimal domain sizes and highest domain wall densities are obtained with intermediate electric field applied along nonpolar axis of ferroelectric crystals, while lower and higher fields produce coarser domains, and temperature also plays important role in domain size control. The simulation shows that selection of polar domain variants by external electric field during nucleation stage of ferroelectric phase transition significantly affects subsequent domain growth and evolution kinetics, controlling the formation and sizes of lamellar domains.

Highly Selective Polymer Electrolyte Membranes from Reactive Block Polymers

A series of reactive poly(norbornenylethylstyrene-s-styrene)-poly(n-propyl-p-styrenesulfonate) (PNS−PSSP) block polymers were prepared by atom transfer radical polymerization. Solutions containing PNS−PSSP, the cyclic olefins dicyclopentadiene and/or cyclooctene, and the second-generation Grubbs metathesis catalyst were prepared, cast as thin films, and allowed to cure at room temperature by a ring-opening metathesis polymerization mechanism. Small-angle X-ray scattering (SAXS) data on cured films were consistent with the formation of nanostructured materials containing PSSP domains confined in a cross-linked matrix of the metathesis-reactive PNS block and the poly(cyclic olefins). The PSSP phase in these films was converted into the sulfonic acid form by hydrolysis of the propyl sulfonate ester. The resulting cross-linked polymer electrolyte membranes (PEMs) were characterized by SAXS and transmission electron microscopy. A bicontinuous morphology with continuous domains of the sulfonic acid phase supported by a continuous and mechanically robust phase was evident in these films. The molecular weight of the PNS−PSSP block polymer controlled the domain sizes, and the mechanical properties of the membranes could be tuned through the choice of cyclic olefins used. The PEMs exhibited pronounced mechanical and thermal robustness. Furthermore, proton conductivities in all the PEMs were similar to those observed in Nafion (the most frequently used PEM in fuel cells) at high humidity. Select PEMs showed significantly lower methanol crossover than Nafion while maintaining high-saturated proton conductivities, which could result in higher direct methanol fuel cell power densities. This reactive block polymer strategy for the preparation of PEMs is attractive due to the ready formation of bicontinuous structures, the facile control of domain size, and the ability to independently control mechanical and swelling properties of the matrix material.

Domain Size Control in Self-Assembling Rod−Coil Block Copolymer and Homopolymer Blends

The addition of homopolymers to a self-assembling rod−coil block copolymer is demonstrated to be a flexible route toward domain size control. Molecular weight matched rod-like homopolymers interdigitate with the rod-blocks within their respective lamellae. As a result of the interdigitation, the coil blocks must rearrange to occupy more interfacial area resulting in an unprecedented decrease in domain spacing with increasing rod homopolymers. Conversely coil homopolymers were locally solubilized within the coil microdomain resulting in an increase of domain spacing with increasing coil homopolymers. The mechanisms of homopolymers solubilization are in qualitative agreement with predictions made by self-consistent mean-field theory (SCFT) calculations.

Nanoelectromechanics of polarization switching in piezoresponse force microscopy

Nanoscale polarization switching in ferroelectric materials by piezoresponse force microscopy in weak and strong indentation limits is analyzed using exact solutions for coupled electroelastic fields under the tip. Tip-induced domain switching is mapped on the Landau theory of phase transitions, with domain size as an order parameter. For a point charge interacting with a ferroelectric surface, switching by both first and the second order processes is possible, depending on the charge–surface separation. For a realistic tip, the domain nucleation process is first order in charge magnitude and polarization switching occurs only above a certain critical tip bias. In pure ferroelectric or ferroelastic switching, the late stages of the switching process can be described using a point charge model and arbitrarily large domains can be created. However, description of domain nucleation and the early stages of growth process when the domain size is comparable with the tip curvature radius (weak indentation) or the contact radius (strong indentation) requires the exact field structure. For higher order ferroic switching (e.g., ferroelectroelastic), the domain size is limited by the tip–sample contact area, thus allowing precise control of domain size.

Enhanced piezoelectricity of barium titanate single crystals with engineered domain configuration

Abstract Engineered domain configurations with different domain sizes were induced in [111]c oriented tetragonal barium titanate BaTiO3 single crystals, and their piezoelectric properties investigated as a function of domain size. Prior to this study, the dependence of domain configuration on temperature and electric field E was investigated using polarised light microscopy to establish the optimum conditions for domain size control. As a result, above the Curie temperature Tc of 132.2°C, when E greater than 6 kV cm−1 was applied along the [111]c direction, an engineered domain configuration with fine domain structure appeared. Moreover, it was also found that this fine domain structure was still stable at room temperature in the absence of electric field. Finally, the piezoelectric properties were measured using 31 resonators with three domain sizes, and it was found that piezoelectric properties such as d31 and k31 increased significantly with decreasing domain size.

Roughness-Induced Magnetic Domain in Fe Thin Films on Land-and-Groove Structures Studied by Spin-Polarized Secondary Electron Microscopy

The magnetic domain structures of Fe thin films on two-dimensionally arranged land-and-groove structures have been studied by spin-polarized secondary electron microscopy (SP-SEM) under an applied dc field. The coercive force on the land area was found to be higher than that on the groove area under magnetization reversal. The surface roughness measured by atomic force microscopy (AFM) was greater on the land area than on the groove area. The roughness-induced high-coercivity on the land prevented the reversed magnetic domain on the groove from spreading over the land in the initial magnetization reversal. This result indicates that surface roughness is an important factor in domain size control of thin magnetic films.

Domain-size control by global feedback in bistable systems.

We study domain structures in bistable systems such as the Ginzburg-Landau equation. The size of domains can be controlled by a global negative feedback. The domain-size control is applied for a localized spiral pattern.

Nanoscale control of ferroelectric polarization and domain size in epitaxial Pb(Zr0.2Ti0.8)O3 thin films

We demonstrate that atomic force microscopy can be used to precisely manipulate individual sub-50 nm ferroelectric domains in ultrahigh density arrays on high-quality epitaxial Pb(Zr0.2Ti0.8)O3 thin films. Control of domain size was achieved by varying the strength and duration of the voltage pulses used to polarize the material. Domain size was found to depend logarithmically upon the writing time and linearly upon the writing voltage. All domains, including those written with ∼100 ns pulses, remained completely stable for the 7 day duration of the experiment.