Abstract
Plastic crystals are a promising candidate for solid state ionic conductors. In this work, quasielastic neutron scattering is employed to investigate the center of mass diffusive motions in two types of plastic crystalline cyclic alcohols: cyclohexanol and cyclooctanol. Two separate motions are observed which are attributed to long-range translational diffusion (α-process) and cage rattling (fast β-process). Residence times and diffusion coefficients are calculated for both processes, along with the confinement distances for the cage rattling. In addition, a binary mixture of these two materials is measured to understand how the dynamics change when a second type of molecule is added to the matrix. It is observed that, upon the addition of the larger cyclooctanol molecules into the cyclohexanol solution, the cage size decreases, which causes a decrease in the observed diffusion rates for both the α- and fast β-processes.
| Original language | English |
|---|---|
| Pages (from-to) | 6296-6304 |
| Number of pages | 9 |
| Journal | Journal of Physical Chemistry B |
| Volume | 122 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 14 2018 |
Funding
Research conducted at ORNL’s SNS and CNMS was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Financial support was provided by Jülich Center for Neutron Sciences (JCNS). S.G. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under EPSCoR Grant No. DE-SC0012432 with additional support from the Louisiana Board of Regents. T.E. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. We would like to thank Dr. Peter Lunkenheimer and Dr. Alois Loidl for their valuable discussions and Dana Vieweg for the X-ray diffraction measurements.