On the
Origin of Mesoscale Structures in Aqueous Solutions
of Tertiary Butyl Alcohol: The Mystery Resolved
Marián Sedlák
Dmytro Rak
10.1021/jp500953m.s001
https://acs.figshare.com/articles/journal_contribution/On_the_Origin_of_Mesoscale_Structures_in_Aqueous_Solutions_of_Tertiary_Butyl_Alcohol_The_Mystery_Resolved/2315044
We
have performed a detailed experimental study on aqueous solutions
of tertiary butyl alcohol which were a subject of long-standing controversies
regarding the puzzling presence of virtually infinitely stable large-scale
structures in such solutions occurring at length scales exceeding
appreciably dimensions of individual molecules, referred to also as
mesoscale structures. A combination of static and dynamic light scattering
yielding information on solution structure and dynamics and gas chromatography
coupled with mass spectrometry yielding information on chemical composition
was used. We show that tertiary butyl alcohol clearly exhibiting such
structures upon mixing with water does not contain any propylene oxide,
which was previously considered as a source of these structures (an
impurity expected to be present in all commercial samples of TBA).
More importantly, we show that no mesoscale structures are generated
upon addition of propylene oxide to aqueous solutions of TBA. The
ternary system TBA/water/propylene oxide exhibits homogeneous mixing
of the components on mesoscales. We show that the source of the mesoscale
structures is a mesophase separation of appreciably more hydrophobic
compounds than propylene oxide. These substances are explicitly analytically
identified as well as their disappearance upon filtering out the mesoscale
structures by nanopore filtration. We clearly show which substances
are disappearing upon filtration and which are not. This enables us
to estimate with rather high probability the chemical composition
of the mesoscale structures. Visualization of large-scale structures
via nanoparticle tracking analysis is also presented. Video capturing
the mesoscale particles as well as their Brownian motion can be found
in the Supporting Information.
2014-03-13 00:00:00
chemical composition
mesoscale structures
propylene oxide
butyl alcohol
solution
Tertiary Butyl Alcohol
TBA