Ordering and dewetting in spin-coated films of a liquid crystalline main chain polymer

Sapich, Beate; Vix, Armelle B. E.; Rabe, Jürgen P.; Stumpe, Joachim; Wilbert, Götz; Zentel, Rudolf

doi:10.1016/j.tsf.2006.02.021

Cited by 27 publications

(38 citation statements)

References 19 publications

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“…The p-p* transition is influenced by thermal annealing or irradiation due to the modification of the aggregation and the orientation of the chromophores. [35] Thus, the maximum of the narrow absorption band due to the p-p* transition of E-azobenzene chromophores of P100 in chloroform solution is detected at 360 nm, whereas as-prepared cast films show blueshifted and broader p-p* transition bands with a maximum at 344 nm. After annealing in the nematic phase, the p-p* transition band becomes broader, the k max is detected at 365 nm and the absorption at k max decreases.…”

Section: Aggregation Of the Azochromophoresmentioning

confidence: 96%

Photoinduced Chiral Nematic Organization in an Achiral Glassy Nematic Azopolymer

Tejedor

Oriol

Serrano

et al. 2007

Adv Funct Materials

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A liquid crystalline homopolymer that has photoisomerizable methoxyazobenzene groups in the side chain has been synthesized and characterized. Thin films of the nematic glassy phase of this polymer have been processed in order to study the absorption spectra and the vibrational and electronic circular dichroism responses by irradiation with 488 nm circularly polarized light (CPL). Selective reflection of visible light demonstrates that the irradiation of this glassy nematic azopolymer induces a helix as a consequence of the chiral arrangement of the azobenzene units. Moreover, a wedge cell with an aligning layer for planar orientation was filled with the polymer with the aim of investigating the change in the macroscopic optical properties and optical textures of the azopolymer on irradiation with CPL. The transfer of chirality from CPL to azopolymer through chiral conformations is proposed as a model for explaining the supramolecular chirality.

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Section: Aggregation Of the Azochromophoresmentioning

confidence: 96%

Photoinduced Chiral Nematic Organization in an Achiral Glassy Nematic Azopolymer

Tejedor

Oriol

Serrano

et al. 2007

Adv Funct Materials

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“…It should be noted that, the profiles of the corresponding spectra and absorption in the region of the φ-φ * transitions were preserved. In addition, the relative intensity of π-π * absorption band to absorption band around 250 nm which is assigned to the φ-φ * transition of the aromatic ring [4,11], was varied as shown in Figure 3(b). It has been reported that the φ-φ * transition is insensitive to the molecular orientation, consequently, the change in the relative intensity of π-π * absorption band to φ-φ * absorption band (A π-π* /A φ-φ* ) is related to the out-of-plane molecular orientation [4,5].…”

Section: Thermooptical Alignment Behavior Of Pei8m In Solid Filmmentioning

confidence: 99%

“…In literature so far very few papers are published on spontaneous out-of-plane molecular orientation of polymeric liquid crystals (PLCs) [3][4][5][6][7]. Bobrovsky group reported that polyacrylate copolymer containing 4-ethoxy-4'-hexoxyazobenzene and cholesterol groups as side chains showed spontaneous out-of-plane molecular orientation on a glass substrate by annealing at 75˚C, whereas only partial out-of-plane molecular orientation was observed for polyacrylate homopolymer [3].…”

Section: Introductionmentioning

confidence: 99%

Thermal and Photo Alignment Behavior of Polyethylene Imine Having Methoxy Substituent Azobenzene Side Chain Group

Kamruzzaman¹,

Kim²,

Kuwahara³

et al. 2013

OJPChem

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Novel type of polyethylene imine having methoxy (-OCH 3 ) substituent azobenzene side chain group through eight methylene spacer group (PEI8M) was successfully synthesized and characterized by the polymer by 1 H NMR, differential scanning calorimetry, polarized optical microscopic and X-ray diffraction analysis. Synthesized polymer possessed liquid crystalline (LC) properties. Spin coated PEI8M film showed out-of-plane molecular orientation on annealing and non-polarized visible light irradiation. PEI8M in solid film exhibited photoresponsive properties upon irradiation of UV and visible light. PEI8M film also exhibited reversible molecular orientation from random state to out-of-plane and from out-of-plane to random state on annealing, non-polarized UV and visible light irradiation.

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“…However, HP1 has a strong tendency towards crystallization and shows liquid crystallinity (SmA) only in a rather narrow temperature range of DT ¼ 14 K. Polymer HP2, despite showing a broad liquid crystalline SmA phase, [23] forms a higher ordered smectic phase (SmB) at room temperature. In order to suppress crystallinity we investigated the influence of a bulky lateral substituent on the phase behavior of the polymer.…”

Section: Linear Main-chain Polyesters As Reference Polymersmentioning

confidence: 99%

(Photo)crosslinkable Smectic LC Main‐Chain Polymers

Beyer

Braun

Zentel

2007

Macro Chemistry & Physics

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This paper presents the synthetic route to SmA LC main‐chain polymers, that can be (photo)crosslinked without solvent in the bulk phase. They are based on soluble polymalonates, in which higher ordered phases can be suppressed by copolymerization with a laterally brominated biphenyl. Two routes were developed to incorporate the crosslinkable groups into the polyester backbone. The first consists in the incorporation of phenols into the polyester. These phenols are not reactive enough to participate in the transesterification reaction used to build up the polymer, but they can be esterified afterwards with acrylates. Thermally or photochemically created radicals then start the crosslinking. The second route is based on the incorporation of benzophenone as side group. It allows a photochemical crosslinking. Crosslinked fibers (monodomains) show the potential of the smectic LC main‐chain elastomers as actuators.magnified image

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Ordering and dewetting in spin-coated films of a liquid crystalline main chain polymer

Cited by 27 publications

References 19 publications

Photoinduced Chiral Nematic Organization in an Achiral Glassy Nematic Azopolymer

Photoinduced Chiral Nematic Organization in an Achiral Glassy Nematic Azopolymer

Thermal and Photo Alignment Behavior of Polyethylene Imine Having Methoxy Substituent Azobenzene Side Chain Group

(Photo)crosslinkable Smectic LC Main‐Chain Polymers

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