scholarly journals Amphiphilic Block Copolymer Micelles in Selective Solvents: The Effect of Solvent Selectivity on Micelle Formation

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1882 ◽  
Author(s):  
Labeesh Kumar ◽  
Andriy Horechyy ◽  
Eva Bittrich ◽  
Bhanu Nandan ◽  
Petra Uhlmann ◽  
...  
Keyword(s):  
Micelle Formation ◽  
Ex Situ ◽  
Microscopy Imaging ◽  
Aggregation State ◽  
Time Resolved ◽  
Solvent Selectivity ◽  
Selective Solvents ◽  
Block Copolymer Micelles ◽  
The Difference

We investigated the micellar behavior of a series of asymmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers in different P4VP-selective alcoholic solvents. The micellar behavior was further correlated with the spectroscopic ellipsometry results obtained on swelling of PS and P4VP polymer films in the corresponding solvent vapors. The time-resolved (in situ) dynamic light scattering (DLS) measurements, in combination with (ex situ) electron microscopy imaging, revealed information about the aggregation state of PS-b-P4VP BCP in different alcohols and the effect of heat treatment. The ellipsometry measurements allowed us to estimate the difference in solvent selectivity toward PS/P4VP pair. Both DLS and ellipsometric studies suggested that less polar alcohols (i.e., 1-propanol, 1-butanol, and 1-pentanol) are likely to be close to each other in terms of their selectivity toward PS/P4VP pair, whereas more polar ethanol and methanol show the highest and the lowest affinity toward P4VP, respectively.

Kinetic Pathway of the Cylinder-to-Sphere Transition in Block Copolymer Micelles Observed in Situ by Time-Resolved Neutron and Synchrotron Scattering

2013 ◽  
Vol 2 (12) ◽  
pp. 1082-1087 ◽  
Author(s):  
Reidar Lund ◽  
Lutz Willner ◽  
Dieter Richter ◽  
Peter Lindner ◽  
Theyencheri Narayanan
Keyword(s):  
Block Copolymer ◽  
Time Resolved ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

scholarly journals Origin of the Difference in the Resistivity of As-Grown Focused-Ion- and Focused-Electron-Beam-Induced Pt Nanodeposits

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
J. M. De Teresa ◽  
R. Córdoba ◽  
A. Fernández-Pacheco ◽  
O. Montero ◽  
P. Strichovanec ◽  
...  
Keyword(s):  
Voltage Dependence ◽  
Ion Beam ◽  
Carbon Matrix ◽  
Ex Situ ◽  
Semiconducting Materials ◽  
Dual Beam ◽  
Transmission Electron ◽  
The Difference ◽  
Main Component

We study the origin of the strong difference in the resistivity of focused-electron- and focused-Ga-ion-beam-induced deposition (FEBID and FIBID, resp.) of Pt performed in a dual beam equipment using(CH3)3Pt(CpCH3)as the precursor gas. We have performed in-situ and ex-situ resistance measurements in both types of nanodeposits, finding that the resistivity of Pt by FEBID is typically four orders of magnitude higher than Pt by FIBID. In the case of Pt by FEBID, the current-versus-voltage dependence is nonlinear and the resistance-versus-temperature behavior is strongly semiconducting, whereas Pt by FIBID shows linear current-versus-voltage dependence and only slight temperature dependence. The microstructure, as investigated by high-resolution transmission electron microscopy, consists in all cases of Pt single crystals with size about 3 nm embedded in an amorphous carbonaceous matrix. Due to the semiconducting character of the carbon matrix, which is the main component of the deposit, we propose that the transport results can be mapped onto those obtained in semiconducting materials with different degrees of doping. The different transport properties of Pt by FEBID and FIBID are attributed to the higher doping level in the case of FIBID, as given by composition measurements obtained with energy-dispersive X-ray microanalysis.

X-Ray Absorption Spectroscopy as an in-situ Tool in Materials Science

1997 ◽  
Vol 502 ◽  
Author(s):  
T. Ressler ◽  
Joe Wong ◽  
W. Metz
Keyword(s):  
Absorption Spectroscopy ◽  
Materials Science ◽  
Ex Situ ◽  
Structural Studies ◽  
Time Resolved ◽  
X Ray ◽  
Complementary Techniques ◽  
X Ray Absorption ◽  
Established Technique

ABSTRACTIn addition to being an established technique for ex-situ structural studies, x-ray absorption spectroscopy (XAS) has recently been realized to be a powerful tool for in-situ time-resolved investigations in materials science. This paper describes two complementary techniques: quick-scanning EXAFS (QEXAFS) and energy-dispersive XAS (DXAS) which offer time resolution in the seconds and milliseconds range, respectively. Formation of a heterogeneous catalyst from a solid-state reaction of a precursor is presented as an example of a time-resolved XAS application.

In Situ Atomic Force Microscopy Imaging of Block Copolymer Micelles Adsorbed on a Solid Substrate

Langmuir ◽  
2003 ◽  
Vol 19 (24) ◽  
pp. 10449-10453 ◽  
Author(s):  
Simon D. Connell ◽  
Stephen Collins ◽  
Johan Fundin ◽  
Zhuo Yang ◽  
Ian W. Hamley
Keyword(s):  
Atomic Force Microscopy ◽  
Block Copolymer ◽  
Solid Substrate ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Atomic Force Microscopy Imaging ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles

Study on the difference between in-situ and ex-situ catalytic pyrolysis of oily sludge

2021 ◽  
Author(s):  
Qian He ◽  
Shengxiong Huang ◽  
Wei Luo ◽  
Yifeng Su ◽  
Mao Xia ◽  
...  
Keyword(s):  
Catalytic Pyrolysis ◽  
Ex Situ ◽  
Oily Sludge ◽  
The Difference

scholarly journals Breeding seasonality of Chital (Axis axis) in the Hetauda Valley of Nepal

2020 ◽  
Vol 17 ◽  
pp. 174-183
Author(s):  
Arjun Bhusal ◽  
Bijay Neupane ◽  
Sanjeeb Bhattarai ◽  
Aashish Kapali ◽  
Suraj Bhatta ◽  
...  
Keyword(s):  
Ex Situ ◽  
Frequency Data ◽  
Seasonal Peak ◽  
Axis Axis ◽  
Breeding Seasonality ◽  
Antler Cycle ◽  
Monthly Changes ◽  
The Difference ◽  
Vegetation And Climate

Breeding seasonality of Axis axis differs from place to place mainly due to the difference in vegetation and climate. In Nepal, although Chital is found all over the lower Terai region, studies on breeding seasonality are limited. In this study, we observed the annual cycle of antler renewal and casting, monthly changes in frequency of bellowing call and ratio of new born fawn to adult and sub-adult females from October 2016 to March 2019. Seasonal peak of proportion of hard-antlered males was found in June and seasonal peak of bellowing call frequency was found in May. Seasonal peak of fawning occurred in December, January and February, at the beginning of dry season before monsoon, probably to coincide with the energy demanding late lactation season with excessive food available in rainy season. From antler cycle, bellowing call frequency and fawning frequency data, peak breeding season was identified as May-June. This information can be crucial in nutritional management, herd composition, and translocation period determination for in-situ and ex-situ species management programs.

In-Situ crystallization of nano-wires and dots by electron irradiation in a field-emission TEM/STEM

1995 ◽  
Vol 53 ◽  
pp. 242-243
Author(s):  
M. Libera
Keyword(s):  
Field Emission ◽  
Electron Irradiation ◽  
Atomic Displacement ◽  
High Energy ◽  
Ex Situ ◽  
Time Resolved ◽  
First Results ◽  
Carbon Coated ◽  
Power Radiation

Specimen damage and heating by high-energy electron irradiation can be exploited to affect local specimen composition/temperature to drive phase transformations. Field-emission (FEG) sources are especially prone to inducing damage/heating, because their high brightness provides focused ~1nm FWHM/1.0nA probes. The physics of beam heating and damage are reviewed by Reimer (1,2). Heating is related to energy-loss mechanisms broadly summarized by the Bethe formula for stopping power. Radiation damage can cause atomic displacement, ionization, and bond scission. Displacement increases the point-defect concentration. Composition changes occur when displacements eject atoms from the specimen. This paper outlines first results using focused-probe irradiation in a Philips CM20 FEG TEM/STEM to locally crystallize an amorphous 80nm Ge48Te52 film. Ex-situ annealing leads to spherulitic crystallites. The crystallization kinetics have been studied by time-resolved reflectivity (3) and in-situ hot-stage optical microscopy (4). In-situ TEM annealing was done with a single-tilt hot stage. Films were floated from carbon-coated mica onto Cu grids. In-situ annealing under a parallel (low dose) beam leads to crystallization much like the ex-situ studies except that the crystallite morphology is highly anisotropic due to non-uniform film heating (5).

scholarly journals Phase transition of nanoparticulate LiFePO4during high rate cycling

2014 ◽  
Vol 70 (a1) ◽  
pp. C357-C357
Author(s):  
Hao Liu ◽  
Fiona Strobridge ◽  
Olaf Borkiewicz ◽  
Kamila Wiaderek ◽  
Karena Chapman ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Transformation Process ◽  
High Rate ◽  
Ex Situ ◽  
Transformation Mechanism ◽  
Time Resolved ◽  
Diffraction Patterns ◽  
Refinement Strategy ◽  
Non Equilibrium

A fundamental understanding of an electrode material requires the elucidation of its phase transformation mechanism during charge and discharge. Ex situ methods, which are carried out under equilibrium condition, have been widely used in charactering the thermodynamic phases at different states of charge, from which a thermodynamic phase transformation pathway can be constructed. However, ex situ measurements do not always reflect the process occurred in an operating battery as the non-equilibrium operating condition might result in deviations from the thermodynamic process, especially for high-rate materials, such as LiFePO4, which is predicted to exhibit a fundamentally different phase transformation process at high rates [1,2]. To probe the process at high rate, an in situ method with reasonable temporal resolution must be employed. In this work, the high rate galvanostatic cycling process of LiFePO4 nanoparticle electrode in a customised AMPIX cell [3] was investigated in situ by time-resolved synchrotron X-ray powder diffraction. Formation of continuous non-equilibrium solid solution phases between LiFePO4 and FePO4 was observed at 10 C rate. The in situ diffraction patterns were analysed by a refinement strategy that accounts for the asymmetrical diffraction peak profiles due to Li composition variations.

scholarly journals Pathways of cylindrical orientations in PS-b-P4VP diblock copolymer thin films upon solvent vapor annealing

Soft Matter ◽  
2014 ◽  
Vol 10 (39) ◽  
pp. 7753-7761 ◽  
Author(s):  
E. Bhoje Gowd ◽  
Tadanori Koga ◽  
Maya K. Endoh ◽  
Kamlesh Kumar ◽  
Manfred Stamm
Keyword(s):  
Thin Films ◽  
Scanning Force Microscopy ◽  
Ex Situ ◽  
Time Resolved ◽  
Solvent Vapor ◽  
Force Microscopy ◽  
Vapor Annealing ◽  
Scanning Force ◽  
Solvent Vapor Annealing

Pathways that control the orientations of cylindrical microdomains formed in PS-b-P4VP thin films upon annealing in different solvent vapors were clarified using time-resolved in situ GISAXS and ex situ scanning force microscopy.

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