A list of things to bring with you:
By Iuliia:
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I have been collaborating with the Electrical Double Layer group from the University of Tartu since the beginning of 2016. I had been to Tartu once, in March’2016, and this August I have visited the group again. During this visit, I was accompanied by Dr. Marco Preto, Researcher in Novelmar Project from Interdisciplinary Centre of Marine and Environmental Research of the University of Porto.
The host institution received us very warmly. There was no need to settle any bureaucracy procedures – Estonian efficiency does not cease to amaze me. Everything was taken care of in advance, and we immediately got out a working spaces, keys or anything we could need for work. I think such attitude is very important for these short visits.
In Estonia we spent two wonderful weeks with work and leisure interconnected. Most of the time in Tartu we worked closely with Dr. Vladislav Ivaništšev and his team, where very productive work was carried out, with social activity interludes that recharged us with a relaxed exchange of ideas. During this visit, the work on developing of an approach to an analysis of electrical double layer in ionic liquids systems was conducted, and an article on our previously done work was prepared for submission.
Among all the Master and PhD students, that are being trained at the group, Meeri Lembinen must be acknowledged especially. Meeri, besides being a brilliant student, is a perfect manager. I suspect, due to her care and attention we have not got a single problem at the university and during the whole stay were accompanied by her and felt like at home.
I hope, our fruitful collaboration is to be continued!
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Already online our latest communication — a nice study showing how Li-glymes behave differently in bulk and at an interface. Looks so truthful that must be real.
https://doi.org/10.1039/C7CP00837F
Part of the work was performed during a short term scientific mission funded by COST action MP1303.
I was in a three-days academic trip in December 2016 within a collaboration between Skoltech research group of Prof. Maxim Fedorov and Tartu theoretical electrochemistry group. My primary goal was to study 3D-RISM method for calculation of the solvatation of molecules and applying this method in my QSAR researches. During my visit I’ve worked closely with Maksim Mišin. He has trained me the 3D-RISM methodology, workflow, and theoretical background. After that we have done a small project related with application of RISM in deep learning for chemoinformatics tasks. I was inspired by good theoretical and practical skills of researchers in the theoretical electrochemistry group. We discussed a lot about current science challenges, and I hope that mutual exchange of ideas was helpful for both.
Because it was my first visit to Tartu I had have intended to familiarize myself with this town. Maksim Mišin and Dr. Vladislav Ivaništšev have represented me this city and have told me a lot of interesting things about Estonia. I was really enjoyed in this trip, and I hope that I will visit it again.
Sergey Sosnin
A post in JPhys+ about our recent article: Researchers at the Universities of Santiago de Compostela, A Coruña, Tartu, Stratchclyde and Cambridge, shed light on the structure of the electrified interface in mixtures of contaminated ionic liquids in their recently published JPCM letter.
https://jphysplus.iop.org/2016/10/28/soaked-to-the-skin-tuning-ionic-liquids-for-electrochemical-devices/
The article is published here: http://iopscience.iop.org/article/10.1088/0953-8984/28/46/464001
P.S. This publication became possible thanks to the COST CM1206.
P.P.S. Finally they have corrected the authors names!
Fairwell to Meeri Lambinen who goes to study to the Helsinki University for one semester.
From Tartu to Tallinn:
From Tallinn to Halsinki:
Finally, in Helsinki:
The interest towards using ionic liquids as lubricants has been increasing since ca. 2012 [1]. It was demonstrated that the interfacial structures in ionic liquids control the nanoscale friction. Experimental (see refs in [1]) and several computational studies [2–5] revealed that lubricity varies with the number and lateral structure of confined ion layers, which in turn are dependent on the applied potential. This opens a possibility of electrochemical control of friction, in other words a “Tantalizing prospect of tunning friction on small dimensions without changing surfaces with a self-replenishing layer, and could be easily integrated into niche situations, … because ionic liquids are cheaper than existing nonconducting molecular lubricants” (see refs in [1]). At the same time it was shown that the restructuring of the potential dependent interfacial structure happens in ionic liquids on a regular manner [6,7]. Therefore, there is a direct relation between various interfacial properties through the potential dependent interfacial structure [8]. For instance, it has not been marked in the literature that the potential dependent friction force [9–11] is proportional to the potential dependent capacitance [12–14]. The understanding of this structure-based relationship can help in controlling of the nanoscale friction in ionic liquids by a potential-tuned ionic lubricant layer.
During this STSM visit, we have initiated a comprehensive study: formulated a hypothesis, prepared a research plan, and obtained preliminary results. The later reveal a proportionality between potential dependent capacitance and friction force. Such structure-based relationship can be of use in controlling of the nanoscale friction in ionic liquids by an applied potential. Further work should verify the generic mechanism of the electrotunable lubricity and capacity. In the future study we plan to perform a detailed atomistic simulation to enable comparison between specific computational and experimental data.
This research was supported by a short term scientific mission funded by COST action MP1303.
References:
[1] R. Hayes, G.G. Warr, R. Atkin, Structure and Nanostructure in Ionic Liquids, Chem. Rev. 115 (2015) 6357–6426.
[2] R. Capozza, A. Vanossi, A. Benassi, E. Tosatti, Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging, J. Chem. Phys. 142 (2015) 64707.
[3] R. Capozza, A. Benassi, A. Vanossi, E. Tosatti, Electrical charging effects on the sliding friction of a model nano-confined ionic liquid, The Journal of Chemical Physics. 143 (2015) 144703.
[4] O.Y. Fajardo, F. Bresme, A.A. Kornyshev, M. Urbakh, Electrotunable Lubricity with Ionic Liquid Nanoscale Films, Sci. Rep. 5 (2015) 7698.
[5] O.Y. Fajardo, F. Bresme, A.A. Kornyshev, M. Urbakh, Electrotunable Friction with Ionic Liquid Lubricants: How Important Is the Molecular Structure of the Ions?, The Journal of Physical Chemistry Letters. 6 (2015) 3998–4004.
[6] V. Ivaništšev, K. Kirchner, T. Kirchner, M.V. Fedorov, Restructuring of the electrical double layer in ionic liquids upon charging, J. Phys.: Condens. Matter. 27 (2015) 102101.
[7] V. Ivaništšev, S. O’Connor, M.V. Fedorov, Poly(a)morphic portrait of the electrical double layer in ionic liquids, Electrochem. Commun. 48 (2014) 61–64.
[8] M.V. Fedorov, A.A. Kornyshev, Ionic liquids at electrified interfaces, Chem. Rev. 114 (2014) 2978–3036.
[9] J. Sweeney, F. Hausen, R. Hayes, G.B. Webber, F. Endres, M.W. Rutland, R. Bennewitz, R. Atkin, Control of Nanoscale Friction on Gold in an Ionic Liquid by a Potential-Dependent Ionic Lubricant Layer, Phys. Rev. Lett. 109 (2012) 155502.
[10] H. Li, R.J. Wood, M.W. Rutland, R. Atkin, An ionic liquid lubricant enables superlubricity to be “switched on” in situ using an electrical potential, Chem. Commun. 50 (2014) 4368–4370.
[11] H. Li, M.W. Rutland, R. Atkin, Ionic Liquid Lubrication: Influence of Ion Structure, Surface Potential and Sliding Velocity, Phys. Chem. Chem. Phys. 15 (2013) 14616–14623.
[12] M. Drüschler, N. Borisenko, J. Wallauer, C. Winter, B. Huber, F. Endres, B. Roling, New insights into the interface between a single-crystalline metal electrode and an extremely pure ionic liquid: slow interfacial processes and the influence of temperature on interfacial dynamics, Phys. Chem. Chem. Phys. 14 (2012) 5090–5099.
[13] R. Atkin, N. Borisenko, M. Drüschler, S.Z. El Abedin, F. Endres, R. Hayes, B. Huber, B. Roling, An in situ STM/AFM and impedance spectroscopy study of the extremely pure 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate/Au(111) interface: potential dependent solvation layers and the herringbone reconstruction, Phys. Chem. Chem. Phys. 13 (2011) 6849.
[14] R. Costa, C.M. Pereira, A.F. Silva, Charge Storage on Ionic Liquid Electric Double Layer: The Role of the Electrode Material, Electrochim. Acta. 167 (2015) 421–428.
Generic force fields are widely used in molecular level computations. However, in real physical systems, the magnitude and localization of the charges are variable due to the interatomic polarization and the molecular dynamics. There are two ways to take these into account: (i) to reduce the atomic charges to non-integer values or (ii) to include polarizableforces.
In this STSM the latter method was used adding Drude oscillators to the system to add the polarizability to the particles. The polarizable force fields (FFs) developed by the group of Prof. Schroder where used to simulate the mixtures of ionic liquids with classical molecular dynamics. Namely mixture of [EMIm][BF4] and [EMIm]I was used. For comparison, the same system with non-polarizable FFs and the system of pure [EMIm][BF4] using polarizable FFs were simulated.
The main problem with classical MD simulations of ions is that the viscosity is overestimated which comes from the fact of imprecise non-bonding interactions. The polarizable FFs estimate it better and taken from the simulations the diffusion constant for the same system with polarizable FFs was much higher than for non-polarizable (1.03 A2/ns and 0.48 A2/ns respectively for cations). The system of pure [EMIm][BF4] showed that iodine affects the movement of ions as the diffusion constant differs by 10% (1.15 A2/ns for cations in pure system). All in all, the polarizable FFs improves the system and adding the small amount of iodine does not change the diffusion nor the structure that much.
Summer is a great time for research visits, schools as well as vacations. Here is my check list for a safe trip from 2016.
Here is what I would like to add to the list in 2023 (thanks to chatGPT for ideas):
Soon there will be an opportunity to apply money for one-to-ten months-long visits, study and research at the university of Tartu.
Scholarships is offered to foreign master and doctoral students. See more at: http://adm.archimedes.ee/stipendiumid/en/programm-dorapluss/dora-pluss-tegevus-2/#sthash.VPHdRrKc.dpuf
Let us know if you are interested to do some collaborations with us and we are happy to help!
