Tunable CO
2 and non-tunable CO
2 lasers were used for the irradiation of thin polypropylene films. The wavelength of the IR radiation was adjusted in such a way that it coincided exactly with the ...absorbance peak in the spectrum of the polypropylene pattern. In this way, conditions of resonance absorption of IR radiation by polymer films were produced. Strong thermal effects in PP were observed under irradiation at the resonance wavelength. The threshold value of IR power, which causes thermal phenomena in irradiated films was established. We pulled films exposed to established threshold values with a constant speed in the plane normal to the laser beam. Highly developed relief and thin traces were formed depending on the pulling speed. Traces with a width smaller than the wavelength of the incident laser beam were obtained. The IR spectra of irradiated PP films were studied with a FTIR spectrometer. Changes in the spectra of PP films were established using correlation analysis of spectral data. The phenomenon could be applied for obtaining highly developed surface relief, storage of information in polymer films and welding of polymer materials.
The status of fundamental physical constants is discussed. The nature of fundamental physical constants is cleared up, based on the analysis of the Boltzmann constant. A new definition of measurable ...values, 'mathematical' and 'physical' numbers and fundamental physical constants is proposed. Mathematical numbers are defined as values insensitive to the choice of both units and frames of reference, whereas 'physical numbers' are dimensionless values, insensitive to transformations of units and sensitive to the transformations of the frames of reference. Fundamental constants are classified as values sensitive to transformations of the units and insensitive to transformations of the frames of reference. It is supposed that a fundamental physical constant necessarily allows diminishing the number of independent etalons in a system of units.
nema
The suitability of polyvinylidene fluoride films for IR integrated optics applications was demonstrated. Polyvinylidene fluoride is a piezoelectric polymer, which demonstrates high transparency in ...the middle-IR and has several transparent windows in the far-IR. The fabrication of cylindrical microlenses and microlens arrays by CO2 laser irradiation of polyvinylidene fluoride substrates has been demonstrated. Pseudo-spherical microlenses were also fabricated by direct laser writing. Strong piezoelectric properties, high chemical resistance, stability to UV radiation and high continuous-use temperature make PVDF suitable for various IR integrated optics applications.
The use of polyaniline emeraldine base films as antireflection coating for near and middle IR optics elements was studied. The optical quality of ZnSe substrates spin-coated with thin PANI EB layers ...were studied using a Linnik interferometer. The spectral properties of PANI coated ZnSe plates were investigated with FTIR spectrometer. It was shown that PANI coating allows a significant decrease of Fresnel losses in the near and middle IR bands (1.0–6.25
μm). The coating allowed continuous transmission of high power density (up to 3
W/mm
2) of IR radiation produced by CO
2 laser. The laser irradiation damage threshold of the PANI EB coating was studied at a wavelength of 1.5
μm. Microhardness of the coated ZnSe is established as satisfactory.
Our letter focuses on the preparation of polyaniline emeraldine base films doped with selenium. PANI EB and Se were dissolved in dimethylsulfoxide. Thin films of selenium-doped PANI EB were obtained ...by spin-coating of Si and ZnSe substrates with a PANI EB+Se solution in DMSO. We studied the distribution of the selenium in the PANI EB films using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The IR spectra of these thin films were obtained with an FT-IR spectrometer.
It is demonstrated that powerful laser radiation causes changes in absorbance spectra of an epoxy resin, polyethylene and polysulfone. Thin polymer films were located between infrared AgBrCl optical ...fibers and exposed to the radiation of a CO
2 laser. The output of the laser source was varied in the range 0–8.5 W. Absorbance spectra were measured by FTIR spectrometry. It was found that characteristic absorbance peaks of polymers decay under the powerful IR light. The apparent dependence of peak magnitude on IR radiation power has been established. The mathematical theory of the observed effect is presented. We suggest that the effect under discussion is caused by the oxygen-free thermal action of IR radiation on the chemical structure of the polymers. We established that the phenomenon of peak disappearance with both polymers — thermoplastic (including such engineering polymer as polysulfone) and thermosetting — is of a threshold nature. The proposed method is a valuable instrument for the study of degradation processes in polymers.
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