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Research article summary (published Mar 2005):

Reversible color changes in lamella hybrids of poly(diacetylenecarboxylates) incorporated in layered double hydroxide nanosheets.

Full Abstract

The present study is an investigation of a reversible thermal color change induced in lamella hybrids of poly(diacetylenecarboxylates) incorporated in layered double hydroxide (LDH) nanosheets. These poly-[m,n]/LDH hybrids prepared by the photo- or gamma-ray-induced polymerization of diacetylenecarboxylates, i.e., CH(3)(CH(2))(m)()(-)(1)CC-CC(CH(2))(n)()(-)(1)CO(2)(-) (mono-[m,n]), and intercalated in LDH lamella sheets, were observed to develop colors ranging from yellow to blue. The change in color was found to depend greatly on the alkyl carbon numbers of the mono-[m,n] (m,n = 10,11; 5,11; 10,5; 16,1) values. Moreover, the conformational alignment of the mono-[m,n] within the LDH was observed to be a crucial factor in color development, which was greatly affected by the intercalation degrees and extent of poly(ene-yne) linkage elongation of the polymers. For the poly-[m,n]/LDH hybrids investigated, a reversible color change was found to occur repeatedly and remarkably for the poly-[10,11]/LDH hybrid. This color change occurred at temperatures between ca. 20 and 80 degrees C back and forth from purple red to bright orange, in stark contrast to the irreversible color change for poly-[10,11] without LDH. Moreover, DSC and Raman spectroscopic studies of the LDH hybrids showed that the thermochromic temperature corresponded to the phase transition temperature of 80 degrees C. XRD analysis also indicated that the poly-[m,n]/LDH hybrid could retain its lamella structure during such thermochromic color changes, enabling conformational recovery in the polymer chains by a cooling down of the hybrids to temperatures lower than the transition temperature, while the nonhybrid poly-[10,11] powders exhibited an irreversible color change at 60 degrees C, above which the polymer powder turned amorphous.

 

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Author information

Author/s: Itoh, Toshio (T); Shichi, Tetsuya (T); Yui, Tatsuto (T); Takahashi, Hiroki (H); Inui, Yoshihisa (Y); Takagi, Katsuhiko (K);

Affiliation: Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan.

Journal and publication information

Publication Type: Journal Article

Journal: The journal of physical chemistry. B (J Phys Chem B), published in United States. (Language: eng)

Reference: 2005-Mar; vol 109 (issue 8) : pp 3199-206

Dates: Created 2006/07/20; Completed 2007/06/27;

PMID: 16851341, status: PubMed-not-MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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