scholarly journals Shear-solvo defect annihilation of diblock copolymer thin films over a large area

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw3974 ◽  
Author(s):  
Ye Chan Kim ◽  
Tae Joo Shin ◽  
Su-Mi Hur ◽  
Seok Joon Kwon ◽  
So Youn Kim
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Defect Density ◽  
Coarse Grained ◽  
Large Area ◽  
Widespread Application ◽  
Solvent Vapor ◽  
Shear Alignment ◽  
Advanced Sampling ◽  
Free Block

Achieving defect-free block copolymer (BCP) nanopatterns with a long-ranged orientation over a large area remains a persistent challenge, impeding the successful and widespread application of BCP self-assembly. Here, we demonstrate a new experimental strategy for defect annihilation while conserving structural order and enhancing uniformity of nanopatterns. Sequential shear alignment and solvent vapor annealing generate perfectly aligned nanopatterns with a low defect density over centimeter-scale areas, outperforming previous single or sequential combinations of annealing. The enhanced order quality and pattern uniformity were characterized in unprecedented detail via scattering analysis and incorporating new mathematical indices using elaborate image processing algorithms. In addition, using an advanced sampling method combined with a coarse-grained molecular simulation, we found that domain swelling is the driving force for enhanced defect annihilation. The superior quality of large-scale nanopatterns was further confirmed with diffraction and optical properties after metallized patterns, suggesting strong potential for application in optoelectrical devices.

scholarly journals Large Area Graphene Deposition on Hydrophobic Surfaces, Flexible Textiles, Glass Fibers and 3D Structures

Coatings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 183 ◽  
Author(s):  
Guobin Jia ◽  
Jonathan Plentz ◽  
Jan Dellith ◽  
Andrea Dellith ◽  
Ruri Wahyuono ◽  
...  
Keyword(s):  
Self Assembly ◽  
Glass Substrate ◽  
Large Scale ◽  
Low Cost ◽  
Glass Fibers ◽  
Flat Glass ◽  
Peel Test ◽  
Large Area ◽  
Thin Glass ◽  
Graphene Flakes

Graphene and its derivatives have many superior electrical, thermal, mechanical, chemical, and structural properties, and promise for many applications. One of the issues for scalable applications is the lack of a simple, reliable method that allows the deposit of a well-ordered monolayer using low-cost graphene flakes onto target substrates with different surface properties. Another issue is the adhesion of the deposited graphene thin film, which has not been well investigated yet. Following our former finding of a double self-assembly (DSA) process for efficient deposition of a monolayer of graphene flakes (MGFs), in this work we demonstrate that the DSA process can be applied even on very challenging samples including highly hydrophobic polytetrafluoroethylene (PTFE), flexible textiles, complex 3D objects, and thin glass fibers. Additionally, we tested adhesion of the graphene flakes on the flat glass substrate by scotch tape peel test of the MGFs. The results show that the graphene flakes adhere quite well on the flat glass substrate and most of the graphene flakes stay on the glass. These findings may trigger many large-scale applications of low-cost graphene feedstocks and other 2D materials.

scholarly journals Advanced Large-Scale Nanofabrication Route for Ultrasensitive SERS Platforms Based on Precisely Shaped Gold Nanostructures

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1806
Author(s):  
Suzanna Akil ◽  
Rana Omar ◽  
Dmitry Kuznetsov ◽  
Vladimir Shur ◽  
Aotmane En Naciri ◽  
...  
Keyword(s):  
Self Assembly ◽  
Shape Control ◽  
Large Scale ◽  
Pathogen Detection ◽  
Selective Adsorption ◽  
Detection Threshold ◽  
Cost Effective ◽  
Label Free ◽  
Large Area ◽  
Gold Nanocrystal

One of the key issues for SERS-based trace applications is engineering structurally uniform substrates with ultrasensitivity, stability, and good reproducibility. A label-free, cost-effective, and reproducible fabrication strategy of ultrasensitive SERS sensors was reported in this work. Herein, we present recent progress in self-assembly-based synthesis to elaborate precisely shaped and abundant gold nanoparticles in a large area. We demonstrated that shape control is driven by the selective adsorption of a cation (Na+, K+, and H+) on a single facet of gold nanocrystal seeds during the growth process. We studied SERS features as a function of morphology. Importantly, we found a correlation between the shape and experimental SERS enhancement factors. We observed a detection threshold of 10−20 M of bipyridine ethylene (BPE), which matches the lowest value determined in literature for BPE until now. Such novel sensing finding could be very promising for diseases and pathogen detection and opens up an avenue toward predicting which other morphologies could offer improved sensitivity.

scholarly journals Duplication accelerates the evolution of structural complexity in protein quaternary structure

2020 ◽  
Author(s):  
Alexander S. Leonard ◽  
Sebastian E. Ahnert
Keyword(s):  
Gene Duplication ◽  
Lattice Model ◽  
Self Assembly ◽  
Large Scale ◽  
Quaternary Structure ◽  
Protein Complexes ◽  
Structural Complexity ◽  
Data Bank ◽  
Coarse Grained ◽  
Duplication Events

AbstractGene duplication, from single genes to whole genomes, has been observed in organisms across all taxa. Despite its prevalence, the evolutionary benefits of this mechanism are the subject of ongoing debate. Gene duplication can significantly alter the self-assembly of protein quaternary structures, impacting the dosage or interaction proclivity. Here we use a lattice model of self-assembly as a coarse-grained representation of protein complex assembly, and show that it can be used to examine potential evolutionary advantages of duplication. Duplication provides a unique mechanism for increasing the evolvability of protein complexes by enabling the transformation of symmetric homomeric interactions into heteromeric ones. This transformation is extensively observed in in silico evolutionary simulations of the lattice model, with duplication events significantly accelerating the rate at which structural complexity increases. These coarse-grained simulation results are corroborated with a large-scale analysis of complexes from the Protein Data Bank.

Self-Assembly of Large Scale and High-Quality Colloidal Particle Films by Spin-Coating

2011 ◽  
Vol 418-420 ◽  
pp. 876-879
Author(s):  
Zhao Ting Yang ◽  
Qing Xu ◽  
Chao Rong Li
Keyword(s):  
Self Assembly ◽  
Spin Coating ◽  
Large Scale ◽  
Colloidal Particle ◽  
Colloidal Crystal ◽  
Aqueous Suspension ◽  
Hexagonal Structure ◽  
Large Area ◽  
Coating Method ◽  
Optical Applications

Colloidal crystal has attracted much attention both in fundamental crystal growth science and optical applications. This paper reports a simple and efficiency spin-coating method to fabricate high ordered colloidal crystals which have specific structures. We used the cleaned glass slide as substrates, the well dispersity 300nm (±1.2%) polystyrene (PS) spheres aqueous suspension (6.6 wt%) to assemble, and obtained highly organized colloidal crystal thin film by controlling spin-coating condition. Mostly, we got the large area plane hexagonal structure at the first layer and tetragonal construction at the second layer. The mechanism for this stacking way was studied. The obtained thin films were demonstrated by Field emission scanning electron microscope (FESEM) and Fast Fourier transform (FFT).

Investigation on the Large-Scale Synthesis of PbSe Nanocrystals

2012 ◽  
Vol 535-537 ◽  
pp. 310-313
Author(s):  
Jin Zhong Niu ◽  
Gui Min Tian ◽  
Yong Guang Cheng ◽  
Hai Dong Li ◽  
Hao Shan Hao
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Large Area ◽  
High Quality ◽  
One Pot ◽  
Uniform Size ◽  
Transition Electron Microscopy ◽  
Large Scale Synthesis ◽  
The One

Large-scale synthesis of high quality PbSe nanocrystals was conducted with the one-pot method. By this “greener” synthesis route, the use of traditional dangerous pyrophoric trioctylphosphine (TOP) and tributylphosphine (TBP) reagents was avoided. The crystal size and shape were controlled by the reaction time, reaction temperature, and the use of different combinations of surfactants. X-ray diffraction (XRD) and transition electron microscopy (TEM) were used to characterize as-synthesized nanocrystals and demonstrated the rock salt cubic structures and narrow size distributions. More than 3 g of high quality PbSe nanocrystals were synthesized in one reaction by this large-scale one-pot method. The uniform size of as-synthesized nanocrystals promoted the self-assembly of PbSe nanocrystals into large-area ordered superstructures.

scholarly journals Formation of a large-area monolayer of polystyrene film via the spin-coating method

2018 ◽  
Vol 33 (3) ◽  
pp. 246-251
Author(s):  
Almedina Modric-Sahbazovic ◽  
Mirjana Novakovic ◽  
Veljko Djokic ◽  
Izet Gazdic ◽  
Natasa Bibic ◽  
...  
Keyword(s):  
Self Assembly ◽  
Spin Coating ◽  
Large Scale ◽  
High Surface ◽  
Deposition Process ◽  
Solution Concentration ◽  
Large Area ◽  
Experimental Conditions ◽  
Spin Coating Method ◽  
Coating Method

The self-assembly methods, an inexpensive and high throughput technique capable of producing nanostructure arrays, relies on the formation on a monolayer of self-assembled nanospheres. This paper reports on the formation of large-areas monolayer polystyrene particles ~150 nm in diameter onto monocrystalline Si (100) substrates by using the spin-coating method. In this method, the quality of the deposited monolayer is determined by the balance between spinning and solvent evaporation, accounted by two different forces, the centrifugal force and viscous shearing force, and their interplay. The key process parameters which influence the deposition process and determine the properties of polystyrene monolayers such as the spinning rate, time and concentration of PS particles in the solution were studied. By varying the experimental conditions in different steps the films quality can be easily improved and the optimized experimental parameters were achieved. A homogenous and well-ordered PS monolayer with a high surface coverage of ~94 % was formed on a large-area substrate of 1 cm ?1 cm at specific conditions of a 2000 rpm spinning rate, 2 wt. % polystyrene solution concentration and 210 s duration of the spinning process. We conclude that this method can be useful in a variety of applications since it offers a stable and controllable approach to the fabrication of monolayer polystyrene films on a large-scale.

Simulation studies of the interactions between membrane proteins and detergents

2005 ◽  
Vol 33 (5) ◽  
pp. 910-912 ◽  
Author(s):  
P.J. Bond ◽  
J. Cuthbertson ◽  
M.S.P. Sansom
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Self Assembly ◽  
Kinetic Mechanism ◽  
Coarse Grained ◽  
Simulation Studies ◽  
High Resolution Data ◽  
Biologically Relevant ◽  
Structure And Dynamics ◽  
Detergent Interactions

Interactions between membrane proteins and detergents are important in biophysical and structural studies and are also biologically relevant in the context of folding and transport. Despite a paucity of high-resolution data on protein–detergent interactions, novel methods and increased computational power enable simulations to provide a means of understanding such interactions in detail. Simulations have been used to compare the effect of lipid or detergent on the structure and dynamics of membrane proteins. Moreover, some of the longest and most complex simulations to date have been used to observe the spontaneous formation of membrane protein–detergent micelles. Common mechanistic steps in the micelle self-assembly process were identified for both α-helical and β-barrel membrane proteins, and a simple kinetic mechanism was proposed. Recently, simplified (i.e. coarse-grained) models have been utilized to follow long timescale transitions in membrane protein–detergent assemblies.

A Novel Technique for Large-Scale Fabrication of 3D Colloidal Crystals: Suspending Self-Assembly in Water Medium (SSAM)

2021 ◽  
Author(s):  
Zhengting Zhang ◽  
Guiyun Yi ◽  
Xiaodong Wang ◽  
Peng Li ◽  
Zhuoyan Wan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Colloidal Crystals ◽  
Water Medium ◽  
Novel Technique

scholarly journals Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets

2021 ◽  
Vol 13 (15) ◽  
pp. 2877
Author(s):  
Yu Tao ◽  
Siting Xiong ◽  
Susan J. Conway ◽  
Jan-Peter Muller ◽  
Anthony Guimpier ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Imaging System ◽  
Landing Site ◽  
Parameter Tuning ◽  
Processing Parameters ◽  
Input Image ◽  
Large Area ◽  
Laser Altimeter ◽  
Imaging Science

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.

scholarly journals Mean-Field Models for EEG/MEG: From Oscillations to Waves

2021 ◽  
Author(s):  
Áine Byrne ◽  
James Ross ◽  
Rachel Nicks ◽  
Stephen Coombes
Keyword(s):  
Gap Junction ◽  
Large Scale ◽  
Mean Field ◽  
Coarse Grained ◽  
Neural Mass Model ◽  
Neuron Network ◽  
Mass Model ◽  
Mean Field Model ◽  
Neural Mass ◽  
The Rich

AbstractNeural mass models have been used since the 1970s to model the coarse-grained activity of large populations of neurons. They have proven especially fruitful for understanding brain rhythms. However, although motivated by neurobiological considerations they are phenomenological in nature, and cannot hope to recreate some of the rich repertoire of responses seen in real neuronal tissue. Here we consider a simple spiking neuron network model that has recently been shown to admit an exact mean-field description for both synaptic and gap-junction interactions. The mean-field model takes a similar form to a standard neural mass model, with an additional dynamical equation to describe the evolution of within-population synchrony. As well as reviewing the origins of this next generation mass model we discuss its extension to describe an idealised spatially extended planar cortex. To emphasise the usefulness of this model for EEG/MEG modelling we show how it can be used to uncover the role of local gap-junction coupling in shaping large scale synaptic waves.

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