Langmuir‐Blodgett films of polymethacrylates with side chains containing functionalized aromatic schiff's bases

Takahashi, Tôru; Miller, P.; Chen, Y. M.; Samuelson, Lynne A.; Galotti, Dianne M.; Mandal, Braja K.; Kumar, Jayant; Tripathy, Sukant K.

doi:10.1002/polb.1993.090310205

Cited by 19 publications

(11 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This approach has been widely used only for the ATR spectra. 14,15,23,38,39,[53][54][55][56] The basic assumptions of the corresponding procedure are as follows. 14,15,56 By analogy with eq 2, the absorbance A i of the film, measured with the IR radiation polarized along the ith laboratory axis, is written as where M i and E i are the respective projections of the TDM and the electric field vector on the ith axis.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A New Approach to the IR Spectroscopic Study of Molecular Orientation and Packing in Adsorbed Monolayers. Orientation and Packing of Long-Chain Primary Amines and Alcohols on Quartz

and

Rao

2001

J. Phys. Chem. B

View full text Add to dashboard Cite

A new method is suggested for determining the molecular orientation in adsorbed films with uniaxial and biaxial anisotropy from two (s-and p-polarized) IRRAS spectra of the same sample, measured at the optimal angle of incidence. The method is simple, does not use the film thickness, and is internally stable with respect to the uncertainty in the input optical parameters of the anisotropic film. The advantages and limitations of the method are discussed. To validate the method, we determined the orientation of hexadecylamine and hexadecyl alcohol adsorbed on a quartz surface. It is shown that at a concentration above the concentration of 2D precipitation but below the concentration of 3D precipitation, hydrocarbon chains in the adsorbed amine monolayer are well-packed in a monoclinic (biaxial) subcell with a tilt angle of about 30°. Chaotically arranged crystallites of the amine molecules appear at the surface at a concentration higher than the concentration of 3D precipitation. Adsorbed monolayers of the alcohol turn out to have a hexagonal structure, in which the hydrocarbon tails are "flip-flop" positioned and tilted by 25-30°from the surface normal.

show abstract

Section: Methodsmentioning

confidence: 99%

“…The third ("dichroic ratio (DR) fitting") approach consists of extracting the average orientational angles by fitting the DR values. 14,15,22,[36][37][38][39][40] Here, the DR is defined as the ratio of the peak (or integrated) intensity of the absorption band in the s-polarized spectrum, A s , to that in the p-polarized spectrum, A p…”

Section: Introductionmentioning

confidence: 99%

A New Approach to the IR Spectroscopic Study of Molecular Orientation and Packing in Adsorbed Monolayers. Orientation and Packing of Long-Chain Primary Amines and Alcohols on Quartz

and

Rao

2001

J. Phys. Chem. B

View full text Add to dashboard Cite

show abstract

“…The dichroic ratios, R = (absorbance in the p-polarized spectrum)/(that in the s-polarized one), at 2918 cm −1 are plotted as a function of the incident angle from the surface normal, ϕ, for the hybrid films of rac- and Λ-[Ru(bpy) 3 ] 2+ in Figure b. The dichroic ratio ( R ) and the incident angle (ϕ) are related to the tilt angle of the alkyl chain (α) from the surface normal as follows: ,− R = 2 − 2 sin 2 ϕ + false( 3 sin 2 ϕ − 1 false) sin 2 α 2 − sin 2 α …”

Section: Resultsmentioning

confidence: 99%

Visible-Light-Induced Hydrophilic Effect in an Ultrathin Hybrid Film of Titania Nanosheet and an Optical Active Ruthenium(II) Complex Cation

et al. 2010

View full text Add to dashboard Cite

Hybrid multilayers of titania nanosheet, amphiphilic alkylammonium cation, and (rac-or Λ-)Ru(II) complex cation have been prepared by a modified Langmuir-Blodgett technique. When a solution of octadecylammonium chloride (CH 3 (CH 2 ) 17 NH 3 + Cl -: ODAH + Cl -) was spread at an interface between the air and an aqueous dispersion of the negatively charged nanosheets, the nanosheets were adsorbed onto the floating monomolecular film of ODAH + to form a hybrid film at the interface. The surface of the hybrid film deposited on a substrate was immersed in an aqueous [Ru(bpy) 3 ]Cl 2 solution. By repeating these procedures, the hybrid multilayer was fabricated. Electronic and infrared spectra of the multilayers indicated layer-by-layer deposition of the hybrid monolayers. X-ray diffraction patterns of the films showed that the layer structure for the film of Λ-[Ru(bpy) 3 ] 2+ was perturbed rather than that of rac-[Ru(bpy) 3 ] 2+ . The second-harmonic generation (SHG) from the hybrid film of Λ-[Ru(bpy) 3 ] 2+ was much more intense than that from the film of rac-[Ru(bpy) 3 ] 2+ , because the former system included noncentrosymmetric component of the optical active (enantiomeric) Ru(II) complex. The IR spectral data for the film of Λ-[Ru(bpy) 3 ] 2+ indicated that the water content in the film increased by the illumination of visible light at 465 nm. However, only a small increase in the water content was observed for the film of rac-[Ru(bpy) 3 ] 2+ when it was illuminated by the visible light. These results were explained by the following mechanism; the visible light irradiated to the hybrid film of Λ-[Ru(bpy) 3 ] 2+ was changed to the ultraviolet light by the SHG effect of the film, which induced superhydrophilicity on the surface of the titania nanosheet. The water content in the film increased, so that the layer structure was perturbed. On the contrary, the SHG-inactive film of rac-[Ru(bpy) 3 ] 2+ kept the layer structure.

show abstract

“…However, this approach demands a priori knowledge of the polarizability of the adsorbed molecule -a parameter that can be calculated assuming a certain microscopic model of the molecular packing only. The MO in the film can be determined by fitting the dichroic ratio (DR) of a selected band in ATR [517, 518,559,[608][609][610][611][612][613][614][615][616][617] or IRRAS [558,[618][619][620] spectra or the ratio of the band intensities in the metallic IRRAS and normalincidence transmission spectra [551,621], which will be referred to below as the "DR fitting" approach. In the spectroscopy of ultrathin films, the DR is defined as the ratio of the peak (or integrated) intensity of the absorption band in the s-polarized spectrum, A s , to that in the p-polarized spectrum, A p : DR = A s A p .…”

Section: Orientationmentioning

confidence: 99%

“…Some investigators [499,613] evaluated the MSEFs using the so-called two-phase approximation that neglects the film at the interface. This model was found [608] to give more accurate MO results than the three-phase (substrate-film-environment) approximation, which was explained by a significant change in the optical properties as the film thickness decreases from the thick-film regime to the ultrathin regime.…”

Section: Orientationmentioning

confidence: 99%

Interpretation of IR Spectra of Ultrathin Films

2003

Handbook of Infrared Spectroscopy of Ultrathin Films

View full text Add to dashboard Cite

Generally speaking, IR spectral measurements of ultrathin films are undertaken to determine (i) the chemical identity of adsorbed species (including dissociation fragments); (ii) the geometric or structural arrangement (orientation) of these species and their positions with respect to the surface atoms of the substrate; (iii) their vibrational, rotational, and translational motion on the surface; (iv) the charge distribution and energy level structure of the valence electrons in both adsorbate and substrate; and (v) the effects of external perturbations, such as the electric and magnetic fields, photons, electrons, heating, and surface pressure on factors (i)-(iv) [1]. However, such information cannot be extracted directly from the IR spectra of ultrathin films due to the strong dependence of the shape and relative intensity of the bands on the geometry of the experiment, the optical properties of the substrate, the surroundings, the gradient of the optical properties at the film-substrate interface and in the film itself, as well as on the film thickness, and the particle size in the case of powder or islandlike supports. These effects and their physical background are discussed in Sections 3.1-3.5 and 3.9. In addition, there can be an intensity transfer between modes of coadsorbed species and a change in the band position with surface coverage. This effect is used for determining the mode of the surface filling and the degree of intermixing of different species at the surface (Section 3.6). If the film under study is located at the electrode-solution interface, the resulting spectrum is made up of contributions of all species in the path of radiation that are affected by the electrode potential, which further complicates the interpretation. Apart from technical means (Chapter 4), there exist analytical and mathematical approaches to resolve contributions of different species in such a complex spectrum (Sections 3.7 and 3.8). Another feature of the IR spectra of ultrathin films that is perhaps surprising and unexpected is their sensitivity to the volume fraction, shape, and orientation of inhomogeneities (e.g., pores or inclusions) in the film. Moreover, if the characteristic size of the 140

show abstract

Langmuir‐Blodgett films of polymethacrylates with side chains containing functionalized aromatic schiff's bases

Cited by 19 publications

References 21 publications

A New Approach to the IR Spectroscopic Study of Molecular Orientation and Packing in Adsorbed Monolayers. Orientation and Packing of Long-Chain Primary Amines and Alcohols on Quartz

A New Approach to the IR Spectroscopic Study of Molecular Orientation and Packing in Adsorbed Monolayers. Orientation and Packing of Long-Chain Primary Amines and Alcohols on Quartz

Visible-Light-Induced Hydrophilic Effect in an Ultrathin Hybrid Film of Titania Nanosheet and an Optical Active Ruthenium(II) Complex Cation

Interpretation of IR Spectra of Ultrathin Films

Contact Info

Product

Resources

About