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dc.contributor.authorAlbayrak, C.en_US
dc.contributor.authorBarim G.en_US
dc.contributor.authorDag O.en_US
dc.date.accessioned2016-02-08T09:34:25Z
dc.date.available2016-02-08T09:34:25Z
dc.date.issued2013en_US
dc.identifier.issn9476539en_US
dc.identifier.urihttp://hdl.handle.net/11693/20749
dc.description.abstractHydrated CaCl2, LiI, and MgCl2 salts induce self-assembly in nonionic surfactants (such as C12H 25(OCH2CH2)10OH) to form lyotropic liquid-crystalline (LLC) mesophases that undergo a phase transition to a new type of soft mesocrystal (SMC) under ambient conditions. The SMC samples can be obtained by aging the LLC samples, which were prepared as thin films by spin-coating, dip-coating, or drop-casting of a clear homogenized solution of water, salt, and surfactant over a substrate surface. The LLC mesophase exists up to a salt/surfactant mole ratio of 8, 10, and 4 (corresponding to 59, 68, and 40wt % salt/surfactant) in the CaCl2, LiI, and MgCl2 mesophases, respectively. The SMC phase can transform back to a LLC mesophase at a higher relative humidity. The phase transformations have been monitored using powder X-ray diffraction (PXRD), polarized optical microscopy (POM), and FTIR techniques. The LLC mesophases only diffract at small angles, but the SMCs diffract at both small and wide angles. The broad surfactant features in the FTIR spectra of the LLC mesophases become sharp and well resolved upon SMC formation. The unit cell of the mesophases expands upon SMC transformation, in which the expansion is largest in the MgCl2 and smallest in the CaCl2 systems. The POM images of the SMCs display birefringent textures with well-defined edges, similar to crystals. However, the surface of the crystals is highly patterned, like buckling patterns, which indicates that these crystals are quite soft. This unusual phase behavior could be beneficial in designing new soft materials in the fields of phase-changing materials and mesostructured materials, and it demonstrates the richness of the phase behavior in the salt-surfactant mesophases. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.en_US
dc.language.isoEnglishen_US
dc.source.titleChemistry - A European Journalen_US
dc.relation.isversionofhttp://dx.doi.org/10.1002/chem.201301662en_US
dc.subjectalkali metalsen_US
dc.subjectliquid crystalsen_US
dc.subjectmesophasesen_US
dc.subjectsaltsen_US
dc.subjectsurfactantsen_US
dc.subjectAmbient conditionsen_US
dc.subjectHigher relative humidityen_US
dc.subjectLyotropic liquid crystalen_US
dc.subjectMesophasesen_US
dc.subjectMesostructured materialsen_US
dc.subjectPolarized optical microscopyen_US
dc.subjectPowder X-ray diffraction (pXRD)en_US
dc.subjectSubstrate surfaceen_US
dc.subjectAlkali metalsen_US
dc.subjectCoatingsen_US
dc.subjectFourier transform infrared spectroscopyen_US
dc.subjectLiquid crystalsen_US
dc.subjectNonionic surfactantsen_US
dc.subjectSaltsen_US
dc.subjectSurface active agentsen_US
dc.subjectX ray diffractionen_US
dc.subjectHydrationen_US
dc.titleLyotropic liquid crystal to soft mesocrystal transformation in hydrated salt-surfactant mixturesen_US
dc.typeArticleen_US
dc.departmentDepartment of Chemistry
dc.citation.spage15026en_US
dc.citation.epage15035en_US
dc.citation.volumeNumber19en_US
dc.citation.issueNumber44en_US
dc.identifier.doi10.1002/chem.201301662en_US


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