Optical Properties of Composites Based on Poly(o-phenylenediamine), Poly(vinylenefluoride) and Double-Wall Carbon Nanotubes

Abstract

In this work, synthesis and optical properties of a new composite based on poly(o-phenylenediamine) (POPD) fiber like structures, poly(vinylidene fluoride) (PVDF) spheres and double-walled carbon nanotubes (DWNTs) are reported. As increasing the PVDF weight in the mixture of the chemical polymerization reaction of o-phenylenediamine, the presence of the PVDF spheres onto the POPD fibers surface is highlighted by scanning electron microscopy (SEM). The down-shift of the Raman line from 1421 cm^-1 to 1415 cm^-1 proves the covalent functionalization of DWNTs with the POPD-PVDF blends. The changes in the absorbance of the IR bands peaked around 840, 881, 1240 and 1402 cm^-1 indicate hindrance steric effects induced of DWNTs to the POPD fiber like structures and the PVDF spheres, as a consequence of the functionalization process of carbon nanotubes with macromolecular compounds. The presence of the PVDF spheres onto the POPD fiber like structures surface induces a POPD photoluminescence (PL) quenching process. An additional PL quenching process of the POPD-PVDF blends is reported to be induced in the presence of DWNTs. The studies of anisotropic PL highlight a change of the angle of the binding of the PVDF spheres onto the POPD fiber like structures surface from 50.2° to 38° when the carbon nanotubes concentration increases in the POPD-PVDF/DWNTs composites mass up to 2 wt.%.

Keywords: IR spectroscopy; Raman scattering; carbon nanotubes; photoluminescence; poly(o-phenylenediamine); poly(vinylidene fluoride).

Figure 1

SEM images of the blends based on the POPD fiber like structures and the PVDF spheres corresponding to the A (a), B (b) and C (c) samples. (d) shows the PVDF spheres. (a₁–d₁) show SEM images with magnification of × 1.00K, while in the case of (a₂–d₂), SEM images with magnification × 20.00K are shown.

Figure 2

SEM images of the composites containing the POPD fiber like structures, PVDF spheres and DWNTs for which carbon nanotubes concentration is equal to 0.5 wt.% (the D sample, (a)), 1 wt.% (the E sample, (b)) and 2 wt.% (the F sample, (c)). (d) shows the SEM image of composite based on the POPD-PVDF blends and DWNTs, when the carbon nanotubes concentration is equal to 1 wt.% (the G sample, (d)).

Figure 3

Raman spectra of the POPD-PVDF blends labeled as samples A (black curve, (a)), B (red curve, (a)) and C (blue curve, (a)) as well as the POPD-PVDF/DWNTs composites labeled as samples D (black curve, (b)), E (red curve, (b)) and F (blue curve, (b)).

Figure 4

Raman (a) and IR (b) spectra of the samples labeled as A1, B1 and C1.

Figure 5

IR spectra of the samples labeled as samples A (black curve, (a)), B (red curve, (a)), C (blue curve, (a)), D (black curve, (b)), E (blue curve, (b)) and F (red curve, (b)).

Scheme 1

The chemical reaction of POPD doped with FeCl₄^- ions with PVDF.

Scheme 2

The chemical reaction of POPD doped with FeCl₄ ^– ions with DWNTs.

Scheme 3

The chemical mechanism of the interaction of POPD doped with FeCl₄^- ions with DWNTs.

Figure 6

PLE (1) and PL (2) spectra of the POPD-PVDF blends labeled as samples A (a₁,a₂), B (b₁,b₂) and C (c₁,c₂), recorded at the emission wavelength of 600 nm and the excitation wavelength of 420 nm, respectively.

Figure 7

PLE (1) and PL (2) spectra of the composites based on the POPD-PVDF blends and DWNTs labeled D (a₁,a₂), E (b₁,b₂) and F (c₁,c₂) recorded at the emission wavelength of 600 nm and the excitation wavelength of 420 nm, respectively.

Figure 8

Polarized PL spectra of the POPD-PVDF blends labeled as A (a), B (b) and C (c) samples. All PL spectra were recorded at the excitation wavelength equal to 420 nm.

Figure 9

Polarized PL spectra of the composite materials based on the POPD-PVDF blends and DWNTs labeled with D (a), E (b) and F (c). All PL spectra were recorded at the excitation wavelength equal to 420 nm.