Relation between Packing Density and Thermal Transitions of Alkyl Chains on Layered Silicate and Metal Surfaces

Hendrik Heinz; R. A. Vaia; B. L. Farmer

doi:10.1021/la703019e

Relation between Packing Density and Thermal Transitions of Alkyl Chains on Layered Silicate and Metal Surfaces

Langmuir ◽

10.1021/la703019e ◽

2008 ◽

Vol 24 (8) ◽

pp. 3727-3733 ◽

Cited By ~ 76

Author(s):

Hendrik Heinz ◽

R. A. Vaia ◽

B. L. Farmer

Keyword(s):

Packing Density ◽

Metal Surfaces ◽

Layered Silicate ◽

Thermal Transitions ◽

Alkyl Chains

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Thermal transitions of the drawn film of a nylon 6/layered silicate nanocomposite

Macromolecular Research ◽

10.1007/bf03219031 ◽

2005 ◽

Vol 13 (2) ◽

pp. 156-161 ◽

Cited By ~ 12

Author(s):

Soo-Young Park ◽

Yang-Hwan Cho

Keyword(s):

Layered Silicate ◽

Nylon 6 ◽

Thermal Transitions

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Dehydration behaviour of hexadecyltrimethylammonium-exchanged smectite

Clay Minerals ◽

10.1180/0009855033820091 ◽

2003 ◽

Vol 38 (2) ◽

pp. 225-232 ◽

Cited By ~ 16

Author(s):

S. Y. Lee ◽

S. J . Kim

Keyword(s):

Differential Scanning Calorimetry ◽

Packing Density ◽

Gradual Increase ◽

Interlayer Spacing ◽

Basal Spacing ◽

Scanning Calorimetry ◽

Continuous Increase ◽

X Ray ◽

Alkyl Chains ◽

Interlayer Region

AbstractThe dehydration of hexadecyltrimethylammonium (HDTMA)-exchanged smectites has been studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The basal spacing of hydrated HDTMA-smectites changed with temperature. The 2.5 HDTMA-smectite (i.e. smectite treated with HDTMA equivalent to 2.5 times the CEC) showed a continuous increase in its basal spacing during dehydration up to 200ºC, while the 1.2 HDTMA-smectite showed a significant decrease in basal spacing. It is assumed that the less ordered alkyl chains in the wet state in the interlayer region may be rearranged to ordered chains (e.g. all-trans conformation) during sequential dehydration. This results in a decrease in interlayer spacing in the phase with low organic packing density and a flat-lying array (i.e. 1.2 HDTMA-smectite), and a gradual increase in the basal spacing when the chains have a vertical configuration (2.5 HDTMA-smectite).

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