Investigation of molecular superstructure of hairy rodlike polymers by X-ray reflection

Schaub, M.; Mathauer, K.; Schwiegk, S.; Albouy, Pierre‐Antoine; Wenz, Gerhard; Wegner, Gerhard

doi:10.1016/0040-6090(92)90268-g

Cited by 28 publications

(8 citation statements)

References 9 publications

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“…In the moment, we cannot experimentally distinguish between the two possibilities. Nevertheless, the structural similarity of macrocyclic and polymeric acylated amines as well as their perfect miscibility in the mesophase, to our understanding, point to a single, helically folded main chain which is surrounded radially by the alkyl side chains, adopting a shape similar to hairy rod systems . Figure shows the CPK models of such a mesomorphic N -acylated poly(ethylenimine) with a helical main chain conformation.…”

Section: Resultsmentioning

confidence: 99%

Formation of Hexagonal Columnar Mesophases by Linear and Branched Oligo- and Polyamides

Seitz¹,

Plesnivy²,

Schimossek³

et al. 1996

Macromolecules

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The formation of columnar mesophases by N-acylated azacrown derivatives may be seen as a consequence of their discoid molecular geometry. Viewing these materials as cyclic oligomers, they are just one example of the various molecular architectures that may be realized based on the N-acylated ethylenamine fragment. By using linear oligoamides, the hexagonal columnar packing is preserved, the monotropic nature of the mesophase reflecting the higher flexibility of the systems. The corresponding polymers are accessible by polymer analogous acylation of linear poly(ethylenimine), in which a high conversion of the amino groups and a low polydispersity of the final polymers can be achieved. The resulting polyamides form enantiotropic mesophases with a hexagonal columnar structure proven by polarizing microscopy, DSC investigations, and X-ray studies. A helically folded structure of the polymer main chain is proposed whereby this structural motif is probably induced by the packing of the alkyl side chains. Based on side group variations, it was found that the 3,4-bis(alkyloxy)benzoyl side group particularly matches the conformative requirements of the polymer main chain for the formation of a columnar structure. Furthermore, a hexagonal columnar mesophase was observed for a non-symmetrically substituted cinnamoyl side group. Whereas in the case of linear polymers the mesophase is stabilized at higher molecular weights, in the case of branched polyamides the enhanced degree of branching disturbs the chain packing. In the same sense, the introduction of chiral groups both in the polymer main chain and in the side-chain region disturbs the packing into an ordered columnar structure. A monotropic mesophase was found for a regularly branched oligoamide with a presumably discoid molecular structure.

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Section: Resultsmentioning

confidence: 99%

Formation of Hexagonal Columnar Mesophases by Linear and Branched Oligo- and Polyamides

Seitz¹,

Plesnivy²,

Schimossek³

et al. 1996

Macromolecules

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“…In contrast, the hydrocarbon tails are either highly tilted or randomly oriented; they may even be intertwined. A comparison may be made between the structure of these films and that of LB films of “hairy rod” polymers …”

Section: Resultsmentioning

confidence: 99%

Structural Properties of Oligomeric Langmuir−Blodgett Films for Second-Order Nonlinear Optics

et al. 1996

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Neutron reflection and infrared spectroscopy have been used to investigate molecular ordering in Langmuir−Blodgett films of oligomers for second-order nonlinear optical applications. The results are compared to those from a previous ellipsometric study. A high degree of order for the chromophores in the multilayer films is revealed by these experiments. In contrast, the hydrocarbon tails are either randomly oriented or highly tilted with respect to the substrate normal. To account for the reduced nonlinear optical activity in thick films, we suggest that some chromophores have become inverted during the deposition process.

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“…The cause for the varying intensity at 1166 cm -1 is probably a preferential orientation parallel to the surface. [5,6] The FT-IR spectrum of 2 strongly differs in the vibration at 1 056 cm -1 . The high intensity with 90 8 polarised radiation and the low intensity with 0 8 polarised radiation are probably due to a preferential orientation parallel to the surface as well.…”

Section: Orientation Of the Cellulose Derivatives On The Aluminium Sumentioning

confidence: 99%

“…[5][6][7][8] It was possible to obtain regenerated cellulose with high biocompatibility by hydrolysing cellulose silylesters. [5] In cooperation with the group of Wegner, [9] we first synthesised hairy-rod molecules for LB-layers on the basis of butyl cellulose substituted with phosphoric acid groups but having a low degree (0.2) of substitution only. We could observe a good adhesion on aluminium and titanium caused by the effect of the phosphoric acid groups.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin layers of phosphorylated cellulose derivatives on aluminium surfaces

Kowalik

Adler²,

Plagge

et al. 2000

Macromol. Chem. Phys.

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In recent works the self‐assembly process has been investigated to replace the present chromating procedure on reactive metals like aluminium and to improve the lacquer adhesion and corrosion inhibition. These self‐assembling layers were formed of small bifunctional organic molecules with phosphate or phosphonic acid groups attached to the metal substrate. The idea of this work was to apply these results and techniques to cellulose derivatives on implant metals. The formation of ultrathin layers of phosphorylated cellulose derivatives has been reported previously. These ultrathin layers were built on metal substrates like aluminium, titanium or steel for adhesion promotion and corrosion inhibition. Hydroxypropyl‐2‐phosphatepropyl cellulose was synthesised for adhesion on hydrophilic metallic surfaces. Hydroxypropyl‐2‐cinnamoylpropylester cellulose was prepared in order to crosslink the adsorbed layers. The layers were formed on metal surfaces via dip coating from dilute solutions and characterised by means of contact angle measurements, SEM investigations and FT‐IR spectroscopy. Initial corrosion tests were performed.

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Investigation of molecular superstructure of hairy rodlike polymers by X-ray reflection

Cited by 28 publications

References 9 publications

Formation of Hexagonal Columnar Mesophases by Linear and Branched Oligo- and Polyamides

Formation of Hexagonal Columnar Mesophases by Linear and Branched Oligo- and Polyamides

Structural Properties of Oligomeric Langmuir−Blodgett Films for Second-Order Nonlinear Optics

Ultrathin layers of phosphorylated cellulose derivatives on aluminium surfaces

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