Raman imaging and photodegradation study of phthalocyanine containing microcapsules and coated particles

Abstract

We present the results of using Raman molecular imaging and atomic force microscopy (AFM) investigation of the composition, stability, and photodegradation of polyelectrolyte multilayer microcapsules and coated microparticles containing copper-phthalocyanine and iron-phthalocyanine. The influence of laser light on degradation of these phthalocyanine dyes embedded in the walls of polyelectrolyte multilayer capsules and shells of microparticles was studied by both AFM and Raman molecular imaging, but only the latter technique gave information on dynamics of photodegradation. Raman peak assignment was performed according to theoretical calculations. The degradation rate of phthalocyanine dyes is estimated from Raman signal measurements and a model is proposed to account for the degradation rate. Practical applications of our approach are outlined.

Layer-by-layer assembled highly absorbing hundred-layer films containing a phthalocyanine dye: Fabrication and photosensibilization by thermal treatment

“…Fig. 4 All measured spectra had several indicative peaks between 500 and 1800 cm -1 corresponding to certain chemical bonds of CuPcTs, and they were in the agreement with the results reported previously [70][71][72]. As seen from the obtained data, most of the band positions observed in the Raman spectra were similar for the analyzed samples (both as-prepared and annealed) in the examined frequency range (500-1800 cm -1 ) (Fig.…”

“…The graphs demonstrate spectra of the deposited coating with the subtraction of the native spectrum of FTO-coated glass. In good agreement with typical spectra of phthalocyanine [47,[66][67][68][70][71][72][73], the absorbance spectra had peaks in the range 300-400 nm (Soret band) and in the 550-750 nm region (Q bands) ( Fig. 1), with a maximum at 330 nm and a dominant peak near 620 nm (with a prominent shoulder at 670 nm), respectively.…”

“…The central metal atom and substituents on the benzene rings of the phthalocyanine molecule influenced UV-vis absorbance; CuPcTs had strong absorption bands around 650 nm (Q bands) [63][64][65][66][67][70][71][72][73]. The characteristic maxima of CuPcTs were in the 300-800 nm range of the absorbance spectra, which was convenient for the analysis of the semitransparent thin PEI/CuPcTs/(PDADMAC/CuPcTs) n films.…”

Advances in nonlinear optical spectroscopies: a historical perspective of developments and applications presented at ECONOS

“…With the help of tip enhancement, they achieved measurements with a spatial resolution of 60 nm. Bratashov et al used Raman imaging and atomic force microscopy to study the composition, stability, and photo‐degradation of polyelectrolyte multilayer microcapsules and coated microparticles. These hollow particles served as containers for phthalocyanine complexes with iron and copper centers.…”

Development and applications of nonlinear optical spectroscopy – 9th ECONOS / 29th ECW meeting in Bremen, Germany

“…In a similar kind of study, Bratashov et al [13] apply a combination of atomic force microscopy and Raman molecular imaging to investigate different properties of microcapsules, in which phthalocyanine (Pc) molecules were enclosed. Using microRaman spectroscopy the spatial distribution of, e.g.…”