Skip to main content
U.S. flag

An official website of the United States government

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



Jan Leys, Deepa Subramanian, Eva Rodezno, Boualem Hammouda, Mikhail A. Anisimov


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.
Soft Matter


Mesoscale phenomena, small-angle neutron scattering, dynamic light scattering


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], (Accessed July 21, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 15, 2013, Updated October 12, 2021