Implications of the structure for the luminescence properties of NBR–PF blend devices nanostructured as Langmuir–Blodgett films

Barbosa, Camila Gouveia; Faez, Roselena; Caseli, Luciano; Péres, Laura O.

doi:10.1016/j.colsurfa.2013.09.031

Cited by 10 publications

(4 citation statements)

References 30 publications

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“…Under these circumstances there is a relationship between the number of the layer and the maximum at 418 nm. When comparing the results of the blend prepared by casting, spin coating and LB technique we observed that the first maximum occur at 400, 395, and 447 nm, respectively . The film prepared by LB technique has a greater emission spectrum displacement to the red region; however, it presents a more defined spectrum, with a vibrational structure, when compared to the others.…”

Section: Resultsmentioning

confidence: 86%

New Strategy to Prepare Luminescent Blend by Spin Coating

Menandro

Parolin

Barbosa

et al. 2019

Macromolecular Symposia

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The use of blends can be a strategy to obtain new properties or to optimize already existing properties in one of the polymers. In luminescent blends, the presence of a non‐conjugated polymer can maximize its emitting properties. However, the parameters to form this blend are fundamental to obtain homogeneous, translucent and good emission films. The present work analyzed parameters such as solution concentration, solvent, and amount of conjugated polymer, drying time, and drying temperature in order to obtain a luminescent blend. The results showed that these parameters are important in the absorption and emission of the materials, and as little as 5 wt% of the conjugated polymer in the blend allows obtaining an emitting blend with few aggregates.

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Section: Resultsmentioning

confidence: 86%

New Strategy to Prepare Luminescent Blend by Spin Coating

Menandro

Parolin

Barbosa

et al. 2019

Macromolecular Symposia

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“…A solution of PDOF- co -3HTh with a concentration of 0.5 mg·mL –1 was spread on the air–water interface in different aliquots. The stock concentration was chosen based on other studies. , The surface pressure–area (π– A ) isotherms (Figure A) for the copolymer confirm that it presents surface activity, allowing the formation of interfacial films. It is noted that as the volume of PDOF- co -3HTh spread on the interface increases, the monolayer tends to occupy smaller area per monomeric unit for a given surface pressure.…”

Section: Resultsmentioning

confidence: 99%

Langmuir and Langmuir–Blodgett Films of Poly[(9,9-dioctylfluorene)-co-(3-hexylthiophene)] for Immobilization of Phytase: Possible Application as a Phytic Acid Sensor

2020

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In this work, the copolymer poly[(9,9-dioctylfluorene)-co-(3-hexylthiophene)] was employed as a matrix for immobilizing phytase, aiming at the detection of phytic acid. The copolymer was spread on the air–water interface forming Langmuir monolayers and phytase adsorbed from the aqueous subphase. The interactions between the copolymer and the enzyme components were investigated with surface pressure and surface potential–area isotherms, Brewster angle microscopy, and polarization modulation infrared reflection–absorption spectroscopy (PM-IRRAS). The enzyme could be incorporated in the monolayers from the aqueous subphase, expanding the copolymer films and maintaining its secondary structure. The polymeric films presented a morphological heterogeneous pattern at the air–water interface because of the ability of their chains to fold and entangle, causing inherent defects in the organization as well as unbalanced lateral distribution at the air–water interface because of the formation of aggregates. The interfacial films were transferred to solid supports as Langmuir–Blodgett films and characterized by PM-IRRAS and scanning electronic microscopy, which showed not only the co-transfer of the enzyme but also the maintenance of their heterogeneous morphological pattern. The enzymatic activity of the blended film was analyzed by UV–vis spectroscopy and allowed the estimation of the value of the Michaelis constant (13.08 mM), demonstrating the feasibility of the system to selectively detect phytic acid for biosensing purposes.

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“…Polymeric structures are molecularly more complex than classical amphiphiles employed as Langmuir monolayers (such as fatty acids and phospholipids) and usually do not form isotherms with well-defined stages/phases (gaseous, liquid, and solid). Thus, the compression of the monolayer may lead to the formation of aggregates and domains. , However, as this copolymer present acyl chains linked to its backbone structure, the deposition of organic solutions on the water surface may lead to the assembly of structures that can be regularly arranged at the air–water interface after spreading along the surface because of amphiphilic properties of the copolymer. In fact, this was observed for PTPF in previous reports, although slightly different profiles of the π– A isotherm are observed, which may be related to the polydispersity of the samples.…”

Section: Resultsmentioning

confidence: 99%

Conjugated Polymers Blended with Lipids and Galactosidase as Langmuir–Blodgett Films To Control the Biosensing Properties of Nanostructured Surfaces

2019

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The structure of enzymes must be conserved when incorporated in nanoelectronic devices because their activity determines the function of the device as sensors. Among the systems that can retain their conformational structures, Langmuir–Blodgett (LB) films can be useful to exploit the construction of bioelectronic devices organized at the molecular level because biological and polymeric materials can be coupled as ultrathin films for biosensors and actuators. In this paper, we immobilized a β-galactosidase enzyme in the LB films of stearic acid and the conjugated polymer poly[(9,9-dioctylfluorene)-co-thiophene]. After the characterization of the floating films using tensiometry, vibrational spectroscopy, and Brewster angle microscopy, they were transferred to solid supports as LB films, and the catalytic activity of the enzyme could be preserved as analyzed using UV–vis spectroscopy. We noted that the presence of a supramolecular structure formed in the LB films not only conserved the enzyme activity but also exhibited regular and distinctive output signals in all molecular architectures employed in this work. These results are related to the synergism between the compounds on the active layer associated with a surface morphology that facilitated the analyte diffusion because of an adequate molecular accommodation of all components. This work then demonstrates the viability of employing LB films composed of lipids, enzymes, and synthetic polymers as devices for biosensing applications.

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Implications of the structure for the luminescence properties of NBR–PF blend devices nanostructured as Langmuir–Blodgett films

Cited by 10 publications

References 30 publications

New Strategy to Prepare Luminescent Blend by Spin Coating

New Strategy to Prepare Luminescent Blend by Spin Coating

Langmuir and Langmuir–Blodgett Films of Poly[(9,9-dioctylfluorene)-co-(3-hexylthiophene)] for Immobilization of Phytase: Possible Application as a Phytic Acid Sensor

Conjugated Polymers Blended with Lipids and Galactosidase as Langmuir–Blodgett Films To Control the Biosensing Properties of Nanostructured Surfaces

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