Surface-induced organization of<b><i>n</i></b>-alkanes on nanostructured PTFE: I. Brillouin spectroscopic investigations on pentacosane

Jiménez, Rafael Madueño; Krüger, Jan-Kristian; Bohn, K.-P.; Fischer, Christian B.

doi:10.1088/0953-8984/8/41/007

Cited by 10 publications

(15 citation statements)

References 36 publications

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“…The elastic properties of the room-temperature phase of C 25 H 52 on the PIA substrate were characterized in detail in a previous paper. 31 As has been shown in that paper, the combination of different scattering techniques [35][36][37] allows rather easily the determination of the whole elastic tensor of an alkane single crystal.…”

Section: Methodsmentioning

confidence: 82%

“…In order to reduce the number of these defects significantly, we developed a modified Bridgman crystal-growth technique described elsewhere. 31 The crystallization was performed at a rate of ⌬T/⌬tϭ0.005 K/min. After this crystallization procedure, the sample plate can be floated away from the glass plates yielding a free standing crystalline sample.…”

Section: Methodsmentioning

confidence: 99%

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Phase-transition behavior ofn-alkanes on nanostructured polytetrafluorethylene films: Brillouin spectroscopic and calorimetric investigations on pentacosane

et al. 1997

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Large monocrystalline domains of pentacosane (C 25 H 52 ) have been prepared on nanostructured polytetrafluoroethylene films. The acoustic and thermal properties have been investigated around the various phase transitions of the crystalline state of pentacosane using high-performance Brillouin spectroscopy and modulated differential scanning calorimetry. In the crystalline orthorhombic phase the values of the elastic constants are c 22 ϭ7 GPa, c 33 ϭ35 GPa, c 44 ϭ2 GPa. In the R V orthorhombic rotator phase the elastic constants are c 22 ϭ3.35 GPa, c 33 ϭ3.67 GPa, c 44 Ͻ0.05 GPa. The evidenced thermal and acoustic anomalies are discussed in the frame of the accompanying structural changes. ͓S0163-1829͑97͒00737-6͔

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Section: Methodsmentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Phase-transition behavior ofn-alkanes on nanostructured polytetrafluorethylene films: Brillouin spectroscopic and calorimetric investigations on pentacosane

et al. 1997

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“…This procedure finally yields crystalline layers with a thickness close to 10 m. Subsequently, the samples were either rapidly cooled at room temperature ͑i.e., quenched from the melt͒, isothermally crystallized in the rotator phase and/or slowly recrystallized in an unidirectional temperature gradient ͑Bridgman technique͒. [17][18][19] In the latter case, the crystallization was performed at a rate of ⌬T/⌬t ϭ0.005 K/min, the temperature gradient being directed perpendicular to the PTFE sliding direction. After the crystallization procedure, the sample plates, a few micrometers thick, were floated off on water to remove the glass slides.…”

Section: A Materials and Sample Preparationmentioning

confidence: 99%

“…This method yields thin macroscopic, nearly defectless crystal plates particularly suitable to characterize their elastic properties using Brillouin spectroscopy. [17][18][19] In the present study, the orientation of alkane layers, achieved by melt crystallization between two nanostructured PIA substrates, is determined from optical microscopy and grazing incidence x-ray diffraction. The results will serve as a basis for a discussion about the role of the interfacial effects on the structure of organic layers.…”

Section: Introductionmentioning

confidence: 99%

Oriented growth of n-alkanes crystals on nanostructured poly(tetrafluoroethylene) substrates

Damman

Fischer

Krüger

2001

The Journal of Chemical Physics

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Articles you may be interested inMicro-structure evolution of wall based crystals after casting of model suspensions as obtained from Bragg microscopy J. Chem. Phys. 137, 094906 (2012); 10.1063/1.4749261 Lamellar nanostructures of silicon heterogeneously solidified on graphite sheets Appl. Phys. Lett. 96, 163113 (2010); 10.1063/1.3407476 Nanoscale domain growth dynamics of ferroelectric poly(vinylidene fluoride-co -trifluoroethylene) thin films Appl. Phys. Lett. 96, 012908 (2010); 10.1063/1.3290247 Orientation and nonlinear optical properties of N-4-nitrophenyl-(L)-prolinol crystals on nanostructured poly(tetrafluoroethylene) substrates Orientation and nonlinear optical properties of 4-(N,N-dimethylamino)-3-acetamidonitrobenzene crystals on nanostructured poly(tetrafluoroethylene) substratesThe growth of n-alkane (C n H 2nϩ2 ) crystals on poly͑tetrafluoroethylene͒ substrates ͑PIA͒ obtained by the friction-transfer method was studied by optical microscopy and grazing incidence x-ray diffraction. The experiments performed on a series of molecules ranging from nϭ21 to nϭ33 reveal the existence of a preferred contact plane with the PIA substrate corresponding to a minimum in lattice mismatch between the two crystallographic systems. Independently of the chain length, the n-alkane crystals tend to orient with their ͑200͒ planes parallel to the substrate, the molecular axis being preferentially aligned along the friction direction of the PTFE substrate. In our study, we demonstrate that the pathways ͑i.e., the orientation mechanisms͒ strongly influence the observed morphology in the low temperature phase.

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“…refs. [1,[15][16][17][18][19]). The elastic properties of alkanes in nanoconfinement, however, were completely neglected and in this paper we present the first study, to our knowledge, on the elasticity of normal alkanes in nanopores.…”

mentioning

confidence: 99%

Elasticity and phase behaviour of n-heptane and n-nonane in nanopores

Schappert

Gemmel

Meisberger

et al. 2015

EPL

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Here we present an ultrasonic study on the elasticity of normal alkanes (n-heptane and n-nonane) in the nanopores of porous Vycor glass (average pore radius ). Above the melting temperature we have found a non-zero shear modulus for both n-heptane and n-nonane, which is also typical for the rotator phases of bulk alkanes at temperatures below the melting temperature. This points to the formation of a special molecular order of the adsorbed alkanes. Furthermore, the alkanes undergo a continuous stiffening over a broad temperature range (of for heptane or for nonane). The results clearly indicate that nanoconfinement induces an extremely broad continuous transition of heptane and nonane into a crystalline low-temperature phase.

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Surface-induced organization ofn-alkanes on nanostructured PTFE: I. Brillouin spectroscopic investigations on pentacosane

Cited by 10 publications

References 36 publications

Phase-transition behavior ofn-alkanes on nanostructured polytetrafluorethylene films: Brillouin spectroscopic and calorimetric investigations on pentacosane

Phase-transition behavior ofn-alkanes on nanostructured polytetrafluorethylene films: Brillouin spectroscopic and calorimetric investigations on pentacosane

Oriented growth of n-alkanes crystals on nanostructured poly(tetrafluoroethylene) substrates

Elasticity and phase behaviour of n-heptane and n-nonane in nanopores

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