Chiral selection of single helix formed by diblock copolymers confined in nanopores

Nanoscale ◽  
2016 ◽  
Vol 8 (35) ◽  
pp. 15961-15969 ◽  
Author(s):  
Hanlin Deng ◽  
Yicheng Qiang ◽  
Tingting Zhang ◽  
Weihua Li ◽  
Tao Yang
1999 ◽  
Vol 77 (8) ◽  
pp. 1311-1326 ◽  
Author(s):  
Neil S Cameron ◽  
Muriel K Corbierre ◽  
Adi Eisenberg

Asymmetric amphiphilic diblock copolymers self-assemble in selective solvents. Since 1995, when we first reported the systematic preparation of a sequence of various "crew-cut" aggregate morphologies from this class of copolymer in solution (1), we have identified a vast array of structures and have begun a detailed investigation of the thermodynamic and kinetic parameters that induce morphogenesis. Not only spheres, rods, bilayer and bicontinuous architectures, as well as inverted structures are observed, but also a selection of mixed, combined and much more complex aggregates is documented. All of these aggregates have a phase-separated insoluble core and a crew-cut soluble corona. Thus, all parameters that permit selective modification of the component of either phase or of the interface provide a window for morphological control. By carefully adjusting the polymer chain environment, it has been possible to develop a systematic understanding of morphogenic parameters, which include, among others, polymer composition, common solvent, initial concentration, temperature, type and concentration of added ions, method of preparation, and added homopolymer. To date, more than 30 publications have appeared in the literature from our group alone on this subject. One of the problems inherent with such a complicated system is the taxonomy or classification: which morphologies correspond to equilibrium positions and which are intermediate or trapped? An attempt at a logical presentation of the observed aggregates is given, preceded by a qualitative discussion of the thermodynamic framework for this system. Where possible, the transitions between morphologies are explained in the context of the thermodynamic parameters. Finally, parallels are drawn between the copolymer aggregates and biological architectures.Key words: crew-cut, morphology, block copolymer, self-assembly, amphiphile.


2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Núria Petit-Garrido ◽  
Josep Claret ◽  
Jordi Ignés-Mullol ◽  
Francesc Sagués

2017 ◽  
Vol 139 (25) ◽  
pp. 8562-8569 ◽  
Author(s):  
Wenge Jiang ◽  
Haihua Pan ◽  
Zhisen Zhang ◽  
S. Roger Qiu ◽  
J. Dongun Kim ◽  
...  

2013 ◽  
Vol 4 ◽  
pp. 04002
Author(s):  
Nuria Petit-Garrido ◽  
Josep Claret ◽  
Jordi Ignés-Mullol ◽  
Francesc Sagués

2007 ◽  
Vol 4 (4) ◽  
pp. 803-817 ◽  
Author(s):  
Matheus Froeyen ◽  
François Morvan ◽  
Jean-Jacques Vasseur ◽  
Peter Nielsen ◽  
Arthur Van Aerschot ◽  
...  

2019 ◽  
Vol 42 ◽  
Author(s):  
Gian Domenico Iannetti ◽  
Giorgio Vallortigara

Abstract Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.


1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.


1978 ◽  
Vol 48 ◽  
pp. 515-521
Author(s):  
W. Nicholson

SummaryA routine has been developed for the processing of the 5820 plates of the survey. The plates are measured on the automatic measuring machine, GALAXY, and the measures are subsequently processed by computer, to edit and then refer them to the SAO catalogue. A start has been made on measuring the plates, but the final selection of stars to be made is still a matter for discussion.


Author(s):  
P.J. Killingworth ◽  
M. Warren

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.


Author(s):  
P. M. Lowrie ◽  
W. S. Tyler

The importance of examining stained 1 to 2μ plastic sections by light microscopy has long been recognized, both for increased definition of many histologic features and for selection of specimen samples to be used in ultrastructural studies. Selection of specimens with specific orien ation relative to anatomical structures becomes of critical importance in ultrastructural investigations of organs such as the lung. The uantity of blocks necessary to locate special areas of interest by random sampling is large, however, and the method is lacking in precision. Several methods have been described for selection of specific areas for electron microscopy using light microscopic evaluation of paraffin, epoxy-infiltrated, or epoxy-embedded large blocks from which thick sections were cut. Selected areas from these thick sections were subsequently removed and re-embedded or attached to blank precasted blocks and resectioned for transmission electron microscopy (TEM).


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