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@INPROCEEDINGS{Niether:818393,
author = {Niether, Doreen and Afanasenkau, Dzmitry and Dhont, Jan
K.G. and Wiegand, Simone},
title = {{T}hermophoretic accumulation in hydrothermal pores},
reportid = {FZJ-2016-04854},
year = {2016},
abstract = {The thermophoretic properties of aqueous formamide
solutions as a function of concentration and temperature are
studied by means of Infra-Red Thermal Diffusion Forced
Rayleigh Scattering. Comparing the results with empirical
concepts to describe the temperature dependence of aqueous
solutions [1] and molecular dynamics simulations of
formamide water mixtures [2] it becomes apparent that the
system only adheres to the empirical equation in a dilute
state and deviates when formamide-formamide interactions
take place at higher concentrations.Formamide is of special
interest in the ‘origin-of-life’ concept as it has been
shown that a number of prebiotic molecules such as purine,
adenine, cytosine and 4(3H)-pyrimidinone form from formamide
under catalytic conditions and at sufficiently high
concentrations [3]. For nucleotides and short DNA strands it
has been shown with numerical finite-element calculations
that a high degree of accumulation in hydrothermal pores
occurs [4]. Using our thermophoretic data on the
formamide/water system, we show that the same combination of
thermophoresis and convection in hydrothermal pores leads to
accumulation of formamide up to concentrations where
nucleobases are formed. The high degree of formamide
accumulation is due to an unusual temperature and
concentration dependence of the thermophoretic behaviour of
formamide. Starting with a formamide concentration of
$10^(-3)$ $wt\%,$ estimated to be typical in shallow lakes
on early earth [5], the accumulation-fold in part of the
pores increases strongly with increasing aspect ratio of the
pores, and saturates to highly concentrated aqueous
formamide solutions of approximately 85 $wt\%$ at large
aspect ratios. References[1] S. Iacopini, R. Rusconi and R.
Piazza, Eur. Phys. J. E, 19, (2006) [2] M. D. Elola and B.
M. Ladanyi, J. Chem. Phys., 125, (2006) [3] S. Pino, J.E.
Sponer, G. Costanzo, R. Saladino and E. Di Mauro, Life, 5,
(2015) [4] P. Baaske, F. M. Weinert, S. Duhr, K. H. Lemke,
M. J. Russell and D. Braun, P. Natl. Acad. Sci. USA, 104,
(2007)[5] S. Miyakawa, H. J. Cleaves and S. L. Miller,
Origins Life Evol. Biosphere, 32, (2002)},
month = {Sep},
date = {2016-09-12},
organization = {4th International Soft Matter
Conference, Grenoble (France), 12 Sep
2016 - 16 Sep 2016},
subtyp = {Invited},
cin = {ICS-3},
cid = {I:(DE-Juel1)ICS-3-20110106},
pnm = {551 - Functional Macromolecules and Complexes (POF3-551)},
pid = {G:(DE-HGF)POF3-551},
typ = {PUB:(DE-HGF)24},
url = {https://juser.fz-juelich.de/record/818393},
}