Organization of polythiophenes at ultrathin films mixed with stearic acid investigated with polarization-modulation infrared reflection–absorption spectroscopy

Silva, Edilene Assunção da; Caseli, Luciano; Olivati, Clarissa de Almeida

doi:10.1016/j.colsurfa.2017.06.035

Cited by 16 publications

(14 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This study of the SA:polymer films, showed that this SA addition to the polymer corroborates the fact that some pristine polymers are not suitable for LB deposition, making it necessary the incorporation of lipid molecules such as SA, to then produce high quality thin films [31]. A clear change on slope of the curves for surface pressure values close to 35 mN/m (Fig.…”

Section: Langmuir Isotherms (π-A)supporting

confidence: 68%

See 1 more Smart Citation

The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

Shiino

Pelosi

Cioffi

et al. 2017

J. of Materi Eng and Perform

View full text Add to dashboard Cite

Low-bandgap organic polymers, poly[(4,4 bis(2 ethylhexyl)cyclopenta [2,1 b:3,4 b′]dithiophene) 2,6 diyl al (2,1,3 benzothiadiazole) 4,7 diyl](PCPDTBT), and poly [(4,4′ dioctyldithieno[3,2 b:2′,3′d] silol 2,6 diyl) alt (2,1,3 benzothiadiazole) 4,7 diyl)], (Si-PCPDTBT) were analyzed at the air-water interface forming a Langmuir monolayer. In order to form stable monolayers and to transfer to solid supports, amphiphilic molecules of stearic acid (SA) were mixed with them. For the pristine polymers, the floating monolayers were transferred onto solid substrates via the Langmuir-Schaefer (LS) technique. Surface pressure-area isotherms and compressibility modulus curves demonstrated that the SA incorporation to the polymers at the air-water interface modified the rheological properties of the Langmuir films, since the films became less compressible at higher pressures and there is clear conformational reorganization taking place at intermediary pressures. The UV-Vis absorption also depicted the changes on the overall film morphology by the shift on the maximum absorption bands, and along with cyclic voltammetry curves the absorption spectra made it possible to estimate the energy diagrams for the polymers. Photoconductivity effects were observed for all the sample, among which the pristine polymers fabricated by LS showed better results, suggesting that the organization provided by the Langmuir-Blodgett (LB) technique was not enough to overcome the insulating characteristic of the SA molecules in this specific configuration.

show abstract

Section: Langmuir Isotherms (π-A)supporting

confidence: 68%

“…A clear change on slope of the curves for surface pressure values close to 35 mN/m (Fig. 1), can be attributed to a molecular accommodation of the polymer over the molecules which are laying on the aqueous subphase while compression is occurring [31].…”

Section: Langmuir Isotherms (π-A)mentioning

confidence: 97%

The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

Shiino

Pelosi

Cioffi

et al. 2017

J. of Materi Eng and Perform

View full text Add to dashboard Cite

show abstract

“…The bands at 2978 and 2874 cm −1 are attributed to asymmetric and symmetric stretching vibration of the C−H bond (CH 3 ). 21,22,27 In the region varying from 1700 to 1350 cm −1 , the bands at 1440, 1410, and 1380 cm −1 are also characteristic of the copolymer, corresponding respectively to the CC stretch of the thiophene ring, CC stretch of the fluorene ring, and C α −C β stretch of the thiophene ring. 21,22 In the same region, characteristic bands of the enzyme can be observed: the ones centered at 1528 and 1564 cm −1 correspond to N−H inplane deformation combined with the C−N stretch (amide II band), and the bands at 1630 and 1649 cm −1 attributed to the CO stretch (amide I band).…”

Section: ■ Results and Discussionmentioning

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The presence of this slope change and these collapses may be ascribed to a liquid‐expanded to liquid‐condensed transition. At this moment, a molecular reorganization takes place on the monolayer, probably because during the compression there is a molecular adaptation of the polymer along the SA molecules at the air−water interface …”

Section: Resultsmentioning

confidence: 99%

Langmuir and Langmuir–Blodgett films of low‐bandgap polymers

Braunger

Silva

Awada

et al. 2018

Polymer International

View full text Add to dashboard Cite

Low‐bandgap conjugated polymers have provided a considerable increase in organic photovoltaic efficiencies, however, an understanding of class‐specific nanostructures, necessary to further improve device qualities, remains scarce. Their self‐assembly and associated electronic behaviors in Langmuir−Blodgett (LB) films are used here to provide relationships specific to each polymer, clarifying their structure−property characteristics. The behavior of two low‐bandgap polymers based on cyclopentadithiophene (PCPDTBT) and dithienosilole (Si‐PCPDTBT) units in the Langmuir trough were investigated and it is shown that it is possible to fabricate nanostructured films of low‐bandgap polymers on solid substrates with the LB deposition technique. The polymers were mixed with amphiphilic molecules at well‐defined concentrations to improve the formation of the LB films. The polymers were also deposited by drop‐casting and LB techniques onto interdigitated electrodes to evaluate their electrical properties, and the LB films were characterized for their optical and morphological properties. It was found that both LB and drop‐cast films of PCPDTBT showed higher electrical conductivities than those of Si‐PCPDTBT. Importantly, LB films resulted in higher electrical conductivities – by an order of magnitude − compared to their equivalent mixtures with stearic acid in drop‐cast films, although drop‐cast films without stearic acid gave higher conductivities. This fine‐tuning of the molecular architectures of the films is thus demonstrated to directly affect the physical properties and may lead to an improvement in device efficiencies in future applications. © 2018 Society of Chemical Industry

show abstract

Organization of polythiophenes at ultrathin films mixed with stearic acid investigated with polarization-modulation infrared reflection–absorption spectroscopy

Cited by 16 publications

References 39 publications

The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

The Role of Stitch Yarn on the Delamination Resistance in Non-crimp Fabric: Chemical and Physical Interpretation

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

Langmuir and Langmuir–Blodgett films of low‐bandgap polymers

Contact Info

Product

Resources

About