scholarly journals Vertical Cylinder-to-Lamella Transition in Thin Block Copolymer Films Induced by In-Plane Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3959
Author(s):  
Alexey S. Merekalov ◽  
Yaroslav I. Derikov ◽  
Vladimir V. Artemov ◽  
Alexander A. Ezhov ◽  
Yaroslav V. Kudryavtsev
Keyword(s):  
Electric Field ◽  
Indium Tin Oxide ◽  
Morphological Changes ◽  
Vertical Cylinder ◽  
Minor Component ◽  
Solvent Vapor ◽  
Copolymer Films ◽  
Atomic Force ◽  
Polystyrene Matrix ◽  
Vinyl Pyridine

Morphological transition between hexagonal and lamellar patterns in thin polystyrene–block–poly(4-vinyl pyridine) films simultaneously exposed to a strong in-plane electric field and saturated solvent vapor is studied with atomic force and scanning electron microscopy. In these conditions, standing cylinders made of 4-vinyl pyridine blocks arrange into threads up to tens of microns long along the field direction and then partially merge into standing lamellas. In the course of rearrangement, the copolymer remains strongly segregated, with the minor component domains keeping connectivity between the film surfaces. The ordering tendency becomes more pronounced if the cylinders are doped with Au nanorods, which can increase their dielectric permittivity. Non-selective chloroform vapor works particularly well, though it causes partial etching of the indium tin oxide cathode. On the contrary, 1,4-dioxane vapor selective to polystyrene matrix does not allow for any morphological changes.

scholarly journals The selectivity of poly(2-vinylpyridine-block-methyl methacrylate) copolymer films: an AFM study

RSC Advances ◽  
2019 ◽  
Vol 9 (29) ◽  
pp. 16455-16466
Author(s):  
Sana Rahim ◽  
Adnan Murad Bhayo ◽  
Ghayas Uddin Siddiqui ◽  
Aneela Maalik ◽  
Najma Memon ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Methyl Methacrylate ◽  
Force Microscopy ◽  
Copolymer Films ◽  
Atomic Force ◽  
Vinyl Pyridine ◽  
Methacrylate Copolymer ◽  
Surface Morphologies

In this study, the surface morphologies of poly(2-vinyl pyridine-block-methyl methacrylate), P(2VP-MMA), copolymer films were analyzed by atomic force microscopy.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

The Electric Field of CO Tips and Its Relevance for Atomic Force Microscopy

Nano Letters ◽  
2016 ◽  
Vol 16 (3) ◽  
pp. 1974-1980 ◽  
Author(s):  
Michael Ellner ◽  
Niko Pavliček ◽  
Pablo Pou ◽  
Bruno Schuler ◽  
Nikolaj Moll ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electric Field ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Tunable control of antibody immobilization using electric field

2015 ◽  
Vol 112 (7) ◽  
pp. 1995-1999 ◽  
Author(s):  
Sam Emaminejad ◽  
Mehdi Javanmard ◽  
Chaitanya Gupta ◽  
Shuai Chang ◽  
Ronald W. Davis ◽  
...  
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Signal To Noise Ratio ◽  
Physical Adsorption ◽  
Antibody Immobilization ◽  
Proof Of Concept ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sensing Platforms ◽  
Glass Surfaces

The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption.

scholarly journals Effects of Solvent Vapor Annealing on Morphology and Charge Transport of Poly(3-hexylthiophene) (P3HT) Films Incorporated with Preformed P3HT Nanowires

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1188
Author(s):  
Mingu Jang ◽  
Yang-Il Huh ◽  
Mincheol Chang
Keyword(s):  
Thin Films ◽  
Charge Transport ◽  
Carrier Mobility ◽  
Morphological Changes ◽  
Charge Carrier Mobility ◽  
Solvent Vapor ◽  
Molecular Ordering ◽  
Vapor Annealing ◽  
Solvent Vapor Annealing ◽  
Influence Of Solvent

We systematically studied the influence of solvent vapor annealing on the molecular ordering, morphologies, and charge transport properties of poly(3-hexylthiophene) (P3HT) thin films embedded with preformed crystalline P3HT nanowires (NWs). Solvent vapor annealing (SVA) with chloroform (CF) was found to profoundly impact on the structural and morphological changes, and thus on the charge transport characteristics, of the P3HT-NW-embedded P3HT films. With increased annealing time, the density of crystalline P3HT NWs was increased within the resultant films, and also intra- and intermolecular interactions of the corresponding films were significantly improved. As a result, the P3HT-NW-embedded P3HT films annealed with CF vapor for 20 min resulted in a maximized charge carrier mobility of ~0.102 cm2 V−1 s−1, which is higher than that of pristine P3HT films by 4.4-fold (μ = ~0.023 cm2 V−1 s−1).

scholarly journals Microwave Spectroscopic Detection of Human Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 118
Author(s):  
Rodica Ionescu ◽  
Raphael Selon ◽  
Nicolas Pocholle ◽  
Lan Zhou ◽  
Anna Rumyantseva ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Stress Disorders ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Conductive Glass ◽  
Hsp70 Protein ◽  
Atomic Force ◽  
Ito Glass ◽  
First Time ◽  
Human Heat Shock Protein

Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.

scholarly journals Deswelling Induced Morphological Changes in Dual pH and Temperature Responsive Ultra-Low Crosslinked Poly (N-Isopropyl Acrylamide)-Co-Acrylic Acid Microgels

2018 ◽  
Author(s):  
Molla Islam ◽  
Maddie Tumbarello ◽  
Andrew Lyon
Keyword(s):  
Light Scattering ◽  
Acrylic Acid ◽  
Morphological Changes ◽  
Scattering Data ◽  
Ionization State ◽  
Force Microscopy ◽  
Temperature Responsive ◽  
Atomic Force ◽  
Isopropyl Acrylamide ◽  
The Impact

<div>We demonstrated the deswelling induced morphological change in dual pH and Temperature responsive ultra-low crosslinked Poly (N-isopropyl acrylamide)-co-acrylic acid microgels. The responsivity with pH and temperature were studied by light scattering and atomic force microscopy. Light scattering data suggest that at pH 4.5 the microgels undergo multiple transitions associated with collapse of pNIPAm-rich segments and repulsion between the AAc-rich segments. The evolution of punctate structures around the periphery or throughout the whole microgels at pH 4.5 and 6.5 respectively was revealed by AFM, further illustrating the heterogeneous deswelling present in the ionized copolymer microgels.</div><div>The impact of this study and understanding how ionization state of copolymer dictates the overall structural properties of microgels will widen our understanding for their applications in biotechnology</div><div><b><br></b></div>

scholarly journals Temperature-Controlled Solvent Vapor Annealing of Thin Block Copolymer Films

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1312 ◽  
Author(s):  
Xiao Cheng ◽  
Alexander Böker ◽  
Larisa Tsarkova
Keyword(s):  
Thin Films ◽  
Block Copolymer ◽  
Thermal Annealing ◽  
Saturated Vapor ◽  
Polymer Chains ◽  
Special Focus ◽  
Solvent Vapor ◽  
Copolymer Films ◽  
Vapor Annealing ◽  
Solvent Vapor Annealing

Solvent vapor annealing is as an effective and versatile alternative to thermal annealing to equilibrate and control the assembly of polymer chains in thin films. Here, we present scientific and practical aspects of the solvent vapor annealing method, including the discussion of such factors as non-equilibrium conformational states and chain dynamics in thin films in the presence of solvent. Homopolymer and block copolymer films have been used in model studies to evaluate the robustness and the reproducibility of the solvent vapor processing, as well as to assess polymer-solvent interactions under confinement. Advantages of utilizing a well-controlled solvent vapor environment, including practically interesting regimes of weakly saturated vapor leading to poorly swollen states, are discussed. Special focus is given to dual temperature control over the set-up instrumentation and to the potential of solvo-thermal annealing. The evaluated insights into annealing dynamics derived from the studies on block copolymer films can be applied to improve the processing of thin films of crystalline and conjugated polymers as well as polymer composite in confined geometries.

scholarly journals Touch-induced seedling morphological changes are determined by ethylene-regulated pectin degradation

2020 ◽  
Vol 6 (48) ◽  
pp. eabc9294
Author(s):  
Qingqing Wu ◽  
Yue Li ◽  
Mohan Lyu ◽  
Yiwen Luo ◽  
Hui Shi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Morphological Changes ◽  
Mechanical Forces ◽  
Ethylene Signaling ◽  
Pectin Degradation ◽  
Force Microscopy ◽  
Mechanical Responses ◽  
Atomic Force ◽  
Wall Stiffness ◽  
Molecular Framework

How mechanical forces regulate plant growth is a fascinating and long-standing question. After germination underground, buried seedlings have to dynamically adjust their growth to respond to mechanical stimulation from soil barriers. Here, we designed a lid touch assay and used atomic force microscopy to investigate the mechanical responses of seedlings during soil emergence. Touching seedlings induced increases in cell wall stiffness and decreases in cell elongation, which were correlated with pectin degradation. We revealed that PGX3, which encodes a polygalacturonase, mediates touch-imposed alterations in the pectin matrix and the mechanics of morphogenesis. Furthermore, we found that ethylene signaling is activated by touch, and the transcription factor EIN3 directly associates with PGX3 promoter and is required for touch-repressed PGX3 expression. By uncovering the link between mechanical forces and cell wall remodeling established via the EIN3-PGX3 module, this work represents a key step in understanding the molecular framework of touch-induced morphological changes.

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