Discotic Liquid Crystals and Polymers In Cylindrical Confinement: Supramolecular Architecture of LC Nanorods and nanotubes Bremen, Complex Materials Summer School C. Stillings 1 , M. Rudisile 1 , M. Steinhart 2 , B. Brandl 1 , U. Gösele 2 , E. Martin 1 , G. Germano 1 , J. H. Wendorff 1 1 Department of Chemistry and Center of Optodynamics, Philipps-Universität Marburg 2 Max Planck Institute of Microstructure Physics, Halle
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Discotic Liquid Crystals and PolymersIn Cylindrical Confinement:
Supramolecular Architecture of LC Nanorods and nanotubes
Bremen, Complex Materials Summer School
C. Stillings1, M. Rudisile1, M. Steinhart2, B. Brandl1, U. Gösele2, E. Martin1, G. Germano1, J. H. Wendorff1
1Department of Chemistry and Center of Optodynamics, Philipps-Universität Marburg
2Max Planck Institute of Microstructure Physics, Halle
MotivationRelevance: two-dimensional LC nanostructures are potential components
of miniaturized devices with specific electronic properties
Task: design of the supramolecular architecture of discotic nanorodsinside porous templates (C. R. Martin, Science 1994, 266, 1961)
Dominant planar orientation(columns parallel to longaxes of template pores) !
Isotropic bulkAda-PBT
Pore diameter:400 nm
Uniaxial orientation of the columns along the pore axis
10 20 300
10000
20000
30000
Θ/2Θ Scans on Aligned Ada-PBT Nanorods
intracolumnardisk-disk distance
2Θ (°)
Cou
nts
10 20 300
15000
30000
45000intercolumnar (100) distance)
Modification of pore walls
Templates have pore walls consisting of alumina
>> polar surface
How does non-polar surface modification
influence texture of mesophase ?
Coating of pore walls with PPX
Chemical vapour
deposition of PPX
Infiltration of Ada-PBT into PPX-coated templates
Poly(paraxylylene):non-polar; high chemical and mechanical stability;
very good insulator
XRD: Θ/2Θ scansXRD on aligned
Ada-PBT nanorods:
Intensity of inter-columnar (100) peak
originates fromhomeotropic phase
Intensity of intra-columnar (001) peak
originates fromplanar phase
Θ/2Θ scans of aligned AdaPBT nanorod in PPX pores
5 10 15 20 25 300
10000
20000
30000
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50000
Inte
nsity
/cou
nts
2Θ/degrees
5 10 15 20 25 300
1000
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Inte
nsity
/cou
nts
2Θ/degrees
5 10 15 20 25 300
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inte
nsity
/cou
nts
2Θ/degrees
Non-modified pore walls:
planar texture
400 nm
35 nm
Non-polar pore walls modified with PPX
>> No texture; bulk-like pattern
Doping of mesophase
Dopants incorporated into Ada-PBT columns
Dopants form charge-transfer complexes with Ada-PBT and influence structural and electronic properties of mesophase(M. Möller, V. Tsukruk, J. H. Wendorff, H. Bengs, H. Ringsdorf,