A molecular ;phase ordering; phase transition leading to a modulated aperiodic composite in n-heptane/urea

Journal Article · Wed Jul 11 00:00:00 EDT 2012 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3692329· OSTI ID:1043083

Mariette, C; Huard, M; Rabiller, P; Nichols, Shane M; Ecolivet, C; Janssen, Ted; Hollingsworth, Mark D; Toudic, B ^[1]

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1. CNRS-UMR

n-Heptane/urea is an aperiodic inclusion compound in which the ratio of host and guest repeats along the channel axis is very close to unity and is found to have a constant value (0.981) from 280 K to 90 K. Below 280 K, two phase transitions are observed. The first (T{sub c1} = 145 K) is a ferroelastic phase transition that generates superstructure reflections for the host while leaving the guest with 1D order. The second (T{sub c2} = 130 K) is a 'phase ordering' transition to a four-dimensional structure (P2{sub 1}11(0{beta}{gamma})) with pronounced host-guest intermodulation and a temperature dependent phase shift between guests in adjacent channels.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: NSFOTHER
• OSTI ID: 1043083
• Journal Information: Journal of Chemical Physics, Vol. 136, Issue 10; ISSN 0021-9606
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
ORGANIC COMPOUNDS
PHASE SHIFT
HEPTANE
UREA