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The interaction force between transcription factor TINY and its corresponding cis-element has been studied with single molecule force microscopy. TINY belongs to the AP2/EREBP family, which is the second largest transcription factor family in plant and plays an important role in the genetic regulation of plant development and growth. The results showed that TINY bound to dehydration-responsive element...
Alignment of single wall carbon nanotubes (SWNT) in liquid crystalline (LC) polymer matrix imparting orientation to the nanotubes along the nematic director was studied by atomic force microscopy, measurements of electrical conductivity and Raman spectroscopy of the composite in the directions parallel and perpendicular to the nematic director. The composites were prepared through dispersion of SWNT...
Tapping mode atomic force microscopy is a technique to measure the topography and properties of surfaces involving a micro-cantilever with a tip at one end that is excited into an oscillation near its resonance frequency. The phase lag between the excitation signal and the observed oscillation is sensitive to local mechanical properties under certain experimental conditions. We have found that by...
The morphology evolution of solution grown polyethylene single crystals has been studied upon annealing below their melting temperature by using atomic force microscopy (AFM). AFM investigations have been performed ex situ, which means AFM investigations at room temperature after the annealing treatment, and in situ at real temperature. Beside the well-known Swiss-cheese and picture frame appearance...
High temperature AFM is used to observe the melting of polyethylene lamellae crystallized from the melt in situ in real-time. Both oriented and un-oriented samples are observed. The melting of shish–kebab structures, including revealing the bare oriented shish, is achieved. Lamellae are observed to melt from their edges, and this is proposed to be due to the inherent higher mobility at the crystal...
Multi-scale force spectroscopy was applied to measure unfolding properties and the internal domain structure of Bombyx mori silk fibroin. We demonstrated that the complex multi-domain sequence and block design in this protein can be directly related to multi-stage unfolding behavior of the specific regions through the use of force extension measurements. These new findings suggest relationships between...
Films of poly[(R)-(−)-2-(3′-thienyl)ethyl-(3′,5″-dinitrobenzoyl)-α-phenylglycinate] were deposited on ITO electrodes by potentiodynamic, potentiostatic and galvanostatic methods using a (C 4 H 9 ) 4 NBF 4 /CH 3 CN electrolyte system containing 20% boron trifluoride diethyl etherate. Polymerisation occurred as a charge dependent process at a potential of 1.4V...
The growth behavior of the rod-like α-form crystals from both the liquid crystal and the isotropic melt state was studied in situ and in real time using a hot-stage atomic force microscopy. The growth rate and direction of the poly(9,9-dioctylfluorene) (PFO) α-form crystals are greatly affected by the orientation of the polymer chains in the liquid crystal matrix. The pre-existence of chain alignment...
A simulation model based on self-consistent mean field theory (SCMFT) has been developed to inspect the approaching process of the polymer chain grafted AFM tip to a substrate. The effects of various controlling parameters, such as grafting position, chain number, chain length, as well as solvent- and substrate-chain interactions, on the force curve were investigated. Real force spectroscopy of AFM...
This report deals with the study of the plastic deformation processes of semi-crystalline polymers at the micrometric and nanometric scales by atomic force microscopy. Capturing images from the same locus of the sample as a function of strain allows in situ observation of the processes. New experimental findings regarding initiation, growth and coalescence of crazes in poly(1-butene) are reported...
Single molecule force spectroscopy (SMFS) is a powerful means in studying the intramolecular and intermolecular interactions in polymer and supramolecular systems, thus opening new horizons for nanomechanic chemistry. This feature article concerns mainly how to employ AFM-based SMFS to obtain some of the important information which is not available by conventional characterizing methods, including...
The relationships between morphology and proton conduction for Nafion membranes and hydrocarbon-type proton exchange membranes, namely, sulfonated poly(arylene ether ether ketone) (S-PEEK) and sulfonated poly(arylene ether sulfone) (S-PES), were investigated by small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). The direct simultaneous observation of surface morphology and active...
This paper describes the orientation of cylindrical domains in thin films of a polystyrene–poly(methylmethacrylate) diblock copolymer (PS-b-PMMA; 0.3 as the PMMA volume fraction) on gold and oxide-coated Si substrates having different surface roughness. Atomic force microscopy images of PS-b-PMMA films having thickness similar to the domain periodicity permitted us to study the effects of substrate...
The plastic deformation of semi-crystalline polybutene (PB) has been studied at the micrometric and nanometric scales by Atomic Force Microscopy (AFM). Owing to a movable tensile drawing stage, capturing images from the same locus of the sample allowed for quasi in situ observations of the plastic processes. In the case of PB films having an average spherulite diameter of about 20μm, the macroscopic...
Morphology development during the crystallization of poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blends was investigated at various crystallization temperatures (T C ) by means of time-resolved light scattering measurements and atomic force microscopy (AFM). A coarse spherulite obtained at a high T C of 162 °C was found to be developed with a two-step crystallization...
Thin films of unmodified and nanoclay-modified polylactide/poly(butylene succinate) (PLA/PBS) blends were prepared on a glass substrate with a spin coater. The morphology and crystal growth behaviours for the films, crystallized at different temperatures, were visualized with atomic force microscope (AFM). AFM images showed that the size of the dispersed PBS phase was reduced on the addition of 2 wt%...
We demonstrate how the wear response of a polymer surface can be efficiently characterized by atomic force microscopy (AFM) using a spiral scan with a thermal tip. If the spiral is scanned at constant angular speed in the vicinity of the glass transition of the polymer, the corrugation of the modified surface is found to decay exponentially with the linear velocity v. This is attested by profiles...
The selective staining by ruthenium tetroxide (RuO 4 ) was used in combination with Atomic Force Microscopy and calcination to discriminate and assign microphases at the surfaces of films of complex polymer systems. This paper evaluates this technique on thin films of polystyrene-b-polylactide (PS-b-PLA) and polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) and demonstrates its efficiency...
The loss tangent of individual components in a blend of polypropylene (PP) and polystyrene (PS) is measured as a function of temperature with contact resonance atomic force microscopy. The loss tangent is calculated directly from the experimentally obtained contact resonance frequency, cantilever quality factor and other operating parameters. The temperature dependent variation of the loss tangent,...
The local mechanical properties of partially cured epoxy resins based on tetraglycidyl methylene dianiline (TGMDA) are proved to be heterogeneous at the nanoscale with the degree of heterogeneity decreasing when the crosslinking density increases. The fully cured resin can be considered homogeneous on both the nano- and macroscale. These conclusions are supported by a comprehensive statistical analysis...
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