NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Mesoscale Phenomena in Solutions of 3-methylpyridine, Heavey Water, and an Antagonistic Salt
Published
Author(s)
Jan Leys, Deepa Subramanian, Eva Rodezno, Boualem Hammouda, Mikhail A. Anisimov
Abstract
We have investigated controversial issues regarding the mesoscale behavior or 3-methylpyridine 93MP), heavy water, and sodium tetraphenylborate (NaBPh4) solutions by combining results obtained from dynamic light scattering (DLS) and small-angle neutron scattering (SANS). We have addressed three questions: (i) What is the origin of the mesoscale inhomogeneities (order of 100 nm in size) manifested by the "slow mode" in DLS? (ii) Is the periodic structure observed from SANS an inherent property of this system? (iii) What is the universality class of critical behavior in this system? Our results confirm that the "slow mode" observed from DLS experiments corresponds to long-lived, highly stable mesoscale droplets (order of 100 nm in size), which occur only when the solute (3MP) is contaminated by hydrophobic impurities. SANS data confirm the presence of a periodic structure with a periodicity of about 10 nm. This periodic structure cannot be eliminated by nanopore filtration and thus is indeed an inherent solution property. The critical behavior of this system in the range of concentration and temperatures investigated by DLS experiments indicates that the criticality belongs to the universality class of the 3-dimensional Ising model.
Leys, J.
, Subramanian, D.
, Rodezno, E.
, Hammouda, B.
and Anisimov, M.
(2013),
Mesoscale Phenomena in Solutions of 3-methylpyridine, Heavey Water, and an Antagonistic Salt, Soft Matter, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914127
(Accessed October 14, 2025)