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National Technical University of Athens School of Chemical Engineering Department of Materials Science and Engineering Computational Materials Science and Engineering Group (Co.M.S.E.) |
| News 28 March 2024 The Chemical Engineering department of the Technical University of Denmark (DTU) is seeking a motivated PhD student who is willing to be part of a world-leading research environment and contribute to the development of thermodynamic models and algorithms for electrolyte solutions. The appointment of this PhD position will be at the Center for Energy Resources Engineering (CERE), Department of Chemical and Biochemical Engineering. Click here for more information. PhD and Postdoctoral opportunities in Applied Knot Theory at ASU. Click here for more information. 6 December 2023 PhD and Postdoctoral opportunities in Applied Knot Theory at ASU. Click here for more information. 20 November 2023 Two PhD positions are available within the framework of the European Network "ReBond". Click here and here for more information. 19 September 2023 PhD position available in Computational Chemistry/Polymers Degradation funded by PlasticUnderground Marie Curie ITN. Click here for more information. 2 September 2023 Masters, PhD, Postdoctoral and Project-Manager positions are available at FORTH-IESL in the field of Synthesis, Experiments and Modelling/Simulations of Soft Matter systems (with emphasis in Polymers and Colloids) for Green and sustainable applications. Click here for more information. 2 September 2023 A PhD position on molecular-dynamics simulations of thermomechanical behaviour of epoxy-copper interfaces is available starting from January 2024 in the Soft Matter and Biological Physics (SMB) group of the Applied Physics department of TU/e. The project will be supervised by prof. dr. Alexey Lyulin. Click here for more information. 12 June 2023 On Friday, the 7th of July, 2023, two distinguished professors from the USA will visit the Computational Materials Science and Engineering (CoMSE) group at NTUA: Professor Bradley Chmelka (Department of Chemical Engineering, University of California, Santa Barbara) and Professor Eleni Panagiotou (School of Mathematical and Statistical Sciences, Arizona State University). In the context of their visit they will give lectures on their research work, with the following titles: Prof. Bradley Chmelka; Compositional and structural order at inorganic-organic interfaces. Prof. Eleni Panagiotou; Novel topological metrics of entanglement in polymers. The lectures will be given in the Koumoutsos room of the School of Chemical Engineering at NTU Athens, starting at 14:00. Click here for more information. 25 April 2023 The 2023 European Conference on Computational and Theoretical Chemistry, co-organized by the Greek Chemists Association and the Division of Computational and Theoretical Chemistry of the European Chemical Society will be held in Thessaloniki, 27-31 August 2023. Click here for more information. 06 April 2023 Doctoral thesis presentation: On Monday, April 24, our PhD student, Mr. Constantinos Revelas, will defend his Doctoral thesis, entitled: "Development of Self-Consistent Field Theory Models for Predicting the Structure and Properties of Inhomogeneous Polymer Systems: Application in Nanocomposite Materials" in front of his seven-member examination committee. The defense will take place at the Koumoutsos room of the Chemical Engineering School at 13:00. Click here to read an extended summary of the PhD. 04 April 2023 Sincerest congratulations to our group leader, Prof. Doros Theodorou, on publishing his autobiography in the Journal of Physical Chemistry B. It is published as a special issue (Festschrift) on the occasion of his 65th birthday. The special issue was edited by Ed Maginn, Ioannis Economou, Randy Snurr, and Arup Chakraborty. Click here to see the cover page or here to access the complete virtual special issue. 03 April 2023 Sincerest congraluations to our PhD students, Mr. Georgios Mikaelian and Mr. Fotis Venetsanos, on winning a doctoral fellowship from the Hellenic Foundation of Research and Innovation (aka ELIDEK). Very well deserved! 24 March 2023 Multiple postdoc positions available at MIT in the research laboratory of Richard Braatz on the integrated continuous manufacturing of mRNA-based biotherapeutics. Click here to find more details on the position and submission process. Read all news... |
Polymer melts at interfaces Understanding the fascinating and complex dynamics of melts of large flexible polymer coils close to solid substrates has been an ongoing challenge for many decades. From the point of view of molecular simulations, the spectrum of length and time scales associated with polymer melts of long chains poses a formidable challenge to studying the long-time dynamics. We have formulated a method, based on combining self-consistent field theory with dynamically corrected transition state theory, for estimating the rates of adsorption and desorption of end-constrained chains e.g., by cross-links or entanglements) from a polymer melt onto a solid substrate. This approach has been successfully applied on a polyethylene/graphite system, where the whole methodology was parameterized by atomistically detailed molecular simulations. For short-chain melts, which can still be addressed by molecular dynamics simulations with reasonable computational resources, the self-consistent field approach gives predictions of the adsorption and desorption rate constants which are gratifyingly close to molecular dynamics estimates.  Figure 1: Schematic illustration of an end-constrained subchain of 50 CH2 units (marked in red), whose residence times in the adsorbed and desorbed state, in the course of an MD simulation, were used for estimating adsorption and desorption kinetics via hazard-plot analysis. External link: http://pubs.acs.org/doi/abs/10.1021/ma501454t To the best of our knowledge, this the first time that the solution of the polymer SCF problem next to a solid surface has been used to provide insight into the dynamics of the system. This work suggests that SCF, coupled with transition-state theory, can give good results for the rate of adsorption/ desorption between polymers in a melt and a surface. SCF theory is less computationally demanding than atomistic simulations, and thus SCF can be used to examine regimes not practically accessible to atomistic simulations, such as the regimes of low adsorption or low desorption rates. Furthermore, the parameters in SCF have been directly connected to atomistic parameters, suggesting that SCF may provide a more faithful description of the problem than alternative, coarse-grained simulation methods. In the regime where molecular dynamics simulation of adsorption rates is practical (short chains, very close to the surface), our results for the adsorption rate are in good agreement with the results from molecular dynamics simulation. Finally, a reasonable agreement between the melt adhesion tension computed from SCF and that measured in atomistic simulations and in experiment, was found.  Figure 2: Adsorption rate constant, predicted by Self Consistent Field / Transition State Theory calculations, is presented as a function of the distance of the ends of an end-constrained subchain from the graphite surface. Both ends are kept at the same distance from the graphite surface, and we consider chain lengths of N = 50 and N = 100 methylenes. Adsorption rates for an end-constrained C50 subchain in a C200 polyethylene melt next to graphite obtained by MD simulation using a detailed united-atom model are also shown. External link: http://pubs.acs.org/doi/abs/10.1021/ma501454t Relevant publications
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