Synthesis of New Side-Chain Liquid-Crystalline Polyoxetanes with Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Campo, Aránzazu del; Bello, A.; Pérez, Ernesto

doi:10.1002/1521-3935(20020401)203:7<975::aid-macp975>3.0.co;2-4

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…This kind of texture is usually associated with the formation of low ordered smectic phases. [11] Pox 2 -C 6 -C 6 and Pox 1 -C 3 Me*-C 6 develop spherulite-like textures that are characteristic of three-dimensional ordered structures, in accordance to the previous DSC results.…”

Section: Identification Of the Mesophasesmentioning

confidence: 93%

“…[9,11] It is found that the general profile of the DSC curves is not significantly modified by the increase in the molecular mass. However, the polymerisation causes a clear shift of the thermal transitions to higher temperatures.…”

Section: Thermal Propertiesmentioning

confidence: 94%

“…[11] Briefly, 4-hydroxy-4 0 -biphenylcarboxylic acid was used as mesogenic precursor, and the flexible chains at both ends, R 2 and R 3 , were attached by reaction with the correspondent alcohol under Mitsunobu conditions. [12] In the last step, the oxetane ring is introduced in the structure by a Williamson etherification of the phenolic group with 3-[(4-methyl-6-bromohexyloxy)methyl]-3-methyloxetane or 3-(6-bromohexyloxy)methyl-3-methyloxetane in a phase-transfer reaction.…”

Section: Synthesismentioning

confidence: 99%

“…A bimodal molecular mass distribution curve was found indicating that the polymerisation reaction leads to a mixture of high molecular mass polymer and some cyclic tetramer, the last being a consequence of the back-biting reaction during the ring opening polymerisation of the oxetane. [11] The final structures and names of the different polymers are summarised in Table 1 (see also table heading for the equivalences of the notation employed). The nature of the three different spacers in the abbreviated names, Pox R3 -R 2 -R 1 , is included in the following way: R 3 is introduced as a subindex designated by 1 or 2 depending on whether R 3 is a 2-butyl or a 2-ethylpropionyl group, respectively.…”

Section: Synthesismentioning

confidence: 99%

“…The values of the associated enthalpy changes (DH % 30 J/g) are similar to those found in main chain poly(bibenzoates) that form crystalline phases. [6,11] By comparing the chemical structure of the polymers with the calorimetric data, the following observations can be pointed out:…”

Section: Thermal Propertiesmentioning

confidence: 99%

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Synchrotron X‐Ray Study of Liquid Crystalline Polyoxetanes Containing Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Campo

Bello

Pérez

2003

Macro Chemistry & Physics

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The study of the mesophase behaviour of a family of new side chain liquid crystalline polymers by means of synchrotron X‐ray diffraction is reported. These systems contain two bibenzoate rigid units in the side chain that are interconnected through a flexible spacer. A polymerisable oxetane unit is linked to one end of the dimer structure, and a flexible terminal chain is linked to the other end. All the polymers form phases with variable degree of order (from low ordered smectic to crystalline) depending on the chemical constitution of the different segments. The influence of the length, parity, and lateral substitution of the spacers on the transitional parameters and the symmetry of the mesophases that are formed is analysed. Close similarities were found between the phase behaviour of the monomer precursors and the derived polyoxetanes. The arrangement of the mesogens, the flexible groups and the polymeric backbone in the layered structure is discussed with respect to the L/d ratio. Different values were obtained depending on the parity of the central spacer and on the degree of order of the mesophase. Interpenetrated structures, where the flexible groups of different lengths are mixed, seem to be compatible with low ordered smectic phases, but sterically disfavoured when building up highly ordered mesophases.

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Section: Identification Of the Mesophasesmentioning

confidence: 93%

Section: Thermal Propertiesmentioning

confidence: 94%

Section: Synthesismentioning

confidence: 99%

Section: Synthesismentioning

confidence: 99%

Section: Thermal Propertiesmentioning

confidence: 99%

See 3 more Smart Citations

Synchrotron X‐Ray Study of Liquid Crystalline Polyoxetanes Containing Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Campo

Bello

Pérez

2003

Macro Chemistry & Physics

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Phase Behaviour of New Side‐Chain Liquid Crystalline Polyoxetanes

Martínez‐Gómez

Bello

Pérez

2005

Macro Chemistry & Physics

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Summary: The synthesis and thermal behaviour of two new polyoxetanes with side chains having a dimer structure mesogen‐spacer‐mesogen and a long terminal alkyl group are reported. The two polymers differ in the chemical structure of the central spacer. The polyoxetanes have been obtained by cationic ring‐opening polymerisation of an appropriately substituted oxetane ring. Both polyoxetanes studied exhibit liquid crystalline properties showing a similar sequence of phases. DSC and synchrotron experiments indicate that a highly ordered phase with a probable orthorhombic packing is observed at low temperature. On heating, this phase melts into a mesophase with hexagonal order within the smectic layers, which, on further heating, is transformed into a disordered smectic mesophase.

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Applications of Synchrotron X-Ray Diffraction to the Study of the Phase Behavior in Liquid Crystalline Polymers

Pérez

Fernandéz‐Blázquez

Martnez-Gómez

et al. 2009

Applications of Synchrotron Light to Scattering and Diffraction in Materials and Life Sciences

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Synthesis of New Side-Chain Liquid-Crystalline Polyoxetanes with Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Cited by 7 publications

References 16 publications

Synchrotron X‐Ray Study of Liquid Crystalline Polyoxetanes Containing Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Synchrotron X‐Ray Study of Liquid Crystalline Polyoxetanes Containing Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

Phase Behaviour of New Side‐Chain Liquid Crystalline Polyoxetanes

Applications of Synchrotron X-Ray Diffraction to the Study of the Phase Behavior in Liquid Crystalline Polymers

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