Electro-optic properties of some oligomeric Langmuir-Blodgett films

Cresswell, J.; Petty, Michael C.; Shearman, J.E.; Allen, S.; Ryan, T.G.; Ferguson, Ian T.

doi:10.1016/0040-6090(94)90631-9

Cited by 9 publications

(9 citation statements)

References 4 publications

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“…For instance, the desired spatial order can be achieved in Langmuir-Blodgett films and self-assembled superlattices. [22][23][24][25][26] More generally, and often most efficiently, the microscopic molecular NLO elements are designed to possess large dipole moments that are ordered by an external field. [27][28][29][30][31][32][33] The current Minireview follows our earlier work [19,[34][35][36][37] and, using the existing theories of dipolar ordering, describes the key factors that determine the efficiency of poling in the formation of macroscopic polarization in NLO materials.…”

Section: Introductionmentioning

confidence: 99%

Macroscopic Order and Electro‐Optic Response of Dipolar Chromophore–Polymer Materials

2004

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This Minireview considers the key factors that govern the organization of macroscopic polarization in nonlinear optical systems obtained by electric poling of organic dipolar chromophores dissolved in polymer matrices. The macroscopic electric polarization depends on the thermodynamic state of the dipole system. The dependence of the paraelectric and antiferroelectric states of dipolar chromophores on the chromophore concentration and the strength of the poling field is discussed. Phase transitions between the para- and antiferroelectric states are investigated within the limits of the Ising and isotropic models for the chromophore dipoles and are considered for varying chromophore concentration, poling field strength, and macroscopic shape of the sample used for poling. The macroscopic polarization and electro-optic coefficient of the material change drastically upon phase transition. The theories are compared with the experimental data on the electro-optic coefficient dependence on the chromophore concentration. The isotropic dipole model shows excellent agreement with experiment for the chromophore systems most commonly used in nonlinear optics.

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Section: Introductionmentioning

confidence: 99%

Macroscopic Order and Electro‐Optic Response of Dipolar Chromophore–Polymer Materials

2004

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“…(a) Ellipsometry. The results of the ellipsometric investigations have been discussed previously and are summarized in Table …”

Section: Resultsmentioning

confidence: 99%

“…III is a higher molecular weight version of I ; since n ≈ 2, it typically contains six active groups. The monolayer formation and LB deposition of these compounds have been described previously 1 Materials used in this work. …”

Section: Methodsmentioning

confidence: 99%

“…Recent attention has therefore focused on the properties of polymeric amphiphiles. We have previously reported on oligomers consisting of a backbone supporting several azobenzene dye groups. , These materials exhibit high second-order electrooptic coefficients (10−20 pm V -1 ) in monolayer form and show excellent LB film deposition characteristics, up to hundreds of layers. Unfortunately, the large electrooptic coefficients of monolayer films are not retained for the thicker structures, contrasting with data for other alternate-layer LB film systems. , …”

Section: Introductionmentioning

confidence: 99%

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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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“…In this article we report the adaptation of this method to the preparation of cellulosic and oligocellulosic copolymers having polysaccharides and polyethylene glycol blocks in the chain backbone, which contain 4‐(4‐nitrophenylazo)‐1‐naphthol as the chromophore. The obtained compounds have potential applications in noncentrosymmetric structures for second‐order nonlinear optics (NLO) 14–19…”

Section: Introductionmentioning

confidence: 99%

Synthesis of block and grafted copolymers containing spacer‐linked chromophore based on cellulose and polyethylene glycol

Namazi

Rad

2004

J of Applied Polymer Sci

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A series of block copolymers from hydroxylterminated cellulose triacetate (HCTA) and cellulose triacetate (CTA) with polyethylene glycol (PEG) were prepared. To activate terminal acid groups in the polyethylene glycols, acid groups were first converted to the acetyl groups with chlorination reaction. In the second series, the cellulose triacetate, having fully substituted acetate groups, was hydrolyzed by the acid catalyst method by using acetic acid and small percentages of water. Then cellulose derivatives containing 4-(4-nitrophenylazo)-1-naphthol (Magneson II) as a chromophore and long hydrocarbon side chains were prepared. The compound 4Ј-bromobutoxy-4-(4-nitrophenylazo)naphthalene was first synthesized from 4-(4-nitrophenylazo)-1-naphthol and 1,4-dibromobutane. The alkylated chromophore reacted with prepared cellulosic and oligocellulosic copolymers in the solution of dimethyl sulfoxide to produce cellulose ethers having the desired chromophore. Polymers containing a mixture of alkyl side chains were also prepared by the addition of 1-bromododecane to the reaction mixture. The above method was used for the preparation of (dodecyl) [4Ј-butoxy-4-(4-nitrophenylazo)naphthalene] (CTA-co-PEG2000) and (dodecyl) [4Ј-butoxy-4-(4-nitrophenylazo)naphthalene] (HCTA-co-PEG2000). The structure of products was determined by FTIR, 1 H-NMR spectroscopy, GPC, and the intrinsic viscosity measurement.

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Electro-optic properties of some oligomeric Langmuir-Blodgett films

Cited by 9 publications

References 4 publications

Macroscopic Order and Electro‐Optic Response of Dipolar Chromophore–Polymer Materials

Macroscopic Order and Electro‐Optic Response of Dipolar Chromophore–Polymer Materials

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

Synthesis of block and grafted copolymers containing spacer‐linked chromophore based on cellulose and polyethylene glycol

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