Theoretical study of optical properties of optical anti-reflection films

In this paper, the theoretical calculation of the characteristics of the optical film, including the basic theory of the film, the calculation of the characteristics of the single-layer film, and the calculation of the characteristics of the multilayer film, to achieve a certain degree of understanding of the characteristics of the optical film. And through the optical anti-reflection film The design principle, material selection, and process mastering have a deeper understanding of the anti-reflection film. The transmission spectrum is used to calculate the “envelope method” The refractive index, thickness, absorption coefficient, an extinction coefficient of the film to analyze the optical performance of the film.

Regularities of changes in the properties of multilayer polymer films depending on their structure

The physical-mechanical, optical and operational properties of three types of multilayer polymer films that are used in the manufacture of laminates for food packaging and differ in the composition and number of layers (from 3 to 9) are studied: transparent based on high-pressure polyethylene; white (containing a white pigment) on the basis of high pressure polyethylene; transparent barrier based on high-pressure polyethylene, polyamide and ethylene copolymer with vinyl alcohol. For comparison, we also used a single-layer film made of high-pressure polyethylene. The films were tested for tensile strength, resistance to delamination of the welded joint, spectral transmittance, optical density, differential scanning calorimetry curves were registered, and gas permeability was determined. To assess the light aging, the film samples were irradiated with a source of ultraviolet light. The following regularities are revealed: the tensile strength of the studied films does not differ significantly, both when changing their composition and the number of layers; a threefold increase in the number of layers leads to a noticeable increase in the elastic modulus of films made of high-pressure polyethylene with a white pigment; barrier film has a higher modulus of elasticity than transparent films based on high-pressure polyethylene; the resistance to delamination of the welded joint increases in the presence of high-pressure polyethylene films with the same number of layers of white pigment and increasing their thickness; increasing the number of layers leads to a decrease in the spectral transmittance and light resistance of transparent films, but does not affect this indicator of films with white pigment; the role of white pigment as an ultraviolet light absorber causes the greatest light resistance of films and its lesser dependence on the number of layers; barrier film in terms of light transmission and resistance to light aging is inferior to transparent films based on high-pressure polyethylene, but it is significantly superior to a single-layer film; the gas permeability of barrier films naturally decreases with increasing thickness, and after light aging significantly increases due to photo-oxidative degradation of polymer layers and, to a greater extent, the layer of ethylene with vinyl alcohol copolymer.

“In-gap” Spectroscopy: Reflected-Wave Phase and Film Characterization

Optical methods that are used to characterize the state of a surface covered with films are based on the measurement of either the ratio between the complex reflection coefficients for mutually orthogonal light polarizations (ellipsometry) or the magnitudes of reflection coefficients themselves; afterward, the parameters of films such as their number, thicknesses, and transparencies can be determined by the fitting, while solving the corresponding inverse problem. In order to extend the set of quantities that can bemeasured experimentally, a method is proposed that allows the phase of the reflected light wave to be determined, by analyzing the spectral features for light reflected from a plane-parallel gap between the surface of analyzed specimen and the environment. In particular, the spectrum obtained, by using the “moving specimen” procedure, can be transformed into the spectral dependences of the magnitude and phase of the reflection coefficient. As a result, the inverse problem of finding the dielectric permittivity of a single-layer film is reduced to the solution of a linear matrix equation, which makes the proposed method more advantageous in comparison with the ellipsometric one, for which there is no direct relationships between the ellipsometric angles and the physical parameters of the film.

FUNCTIONAL THREE-COMPONENT POLYMERIC BIOCOMPOSITES FOR THE TREATMENT OF BEDSORES

Presented here are the results of investigations into the preparation of three-component dressing materials from various biopolymers in the form of a single-layer film which is suitable as a carrier for pain-relieving (lidocaine) and bacteriostatic (sulphanilamid) therapeutic agents. Physical-chemical, biological and usable properties of the prepared materials were tested and assessed. The amount of added active substance was adopted based on the dose recommended by the Polish Pharmacopeia for external medicinal preparations. Antibacterial activity against gram (-) Escherichia coli and gram (+) Staphylococcus aureus was assessed in some of the biocomposites by quantitative methods. The cytotoxic action in direct contact with the mouse fibroblast NCTC clone 929 was also estimated. Thermal analysis (DSC), infrared spectrophotometry (FTIR) and nuclear magnetic resonance spectroscopy were employed to investigate the impact of the variable contents of chitosan, alginate, carboxymethyl cellulose (CMC), and the active substance upon the chemical- and phase-structure of the prepared three-component polymeric biocomposites. It was found that the quantitative composition of the biocomposites and the additive of active substances lidocaine and sulphanilamide exert a vital impact upon their physical-mechanical and usable properties (imbibition, absorption). Investigations into the release of the medicinal substance from the investigated biocomposites to an acceptor fluid led to the conclusion that the kinetics of the process may be described by a complex first order rate equation with two exponential functions.

Low Haze and Antifog Performance of 2-Layer Poly(Lactic Acid) Based Films

For fresh-cut and ready-to-eat packaging films, antifog additives (AFs) are commonly used to suppress the formation of water droplets on film surface. To date, the type and dosage of antifogging for PLA based film are less studied. Therefore, in this research, films incorporated with antifog additive were fabricated by cast extrusion technique. The migration behavior of commercial polyglycerol ester as selected AF was investigated. The cold fog test results showed that 3.5 and 5 wt% of AF in 20PBAT/80PLA single layer film can provide clear films without droplet of water within 7 days and 3 hours, respectively. For 2-layer films, the presented of AF in seal layer as 95(20PBAT/80PLA)/5 (polyglycerol ester) and core layer of PLA were prepared having different thicknesses of seal layer/core layer of 20/15 and 10/15 μm. The migration rate of AF in thin 2-layer film (10/15 μm) appeared to be higher than that in 20/15 μm film. Films’ surface could become clear without water droplet (rating scale > 8) within 4 days for 10/15 μm and 7 days for 20/15 μm films. Haze of films was analyzed by haze meter. Haze of 10/15 μm film was decreased from 7 to 4.4, while that of 20/15 μm film was also decreased from 10 to 7.9 when AF appeared on its surface. Both films can be a peelable PLA based lidding film product with low haze (< 10 %) and antifog performance (within 1 month). In addition, 10/15 μm film can be an easy peel lidding film since its peel strength was in an easy peel range (6-10 N/15 mm).

Thickness and Interface-Dependent Structural, Magnetic, and Transport Properties of Cu/Co Thin Film and Multilayer Structures

Structural, magnetic, and transport properties of electron beam evaporated Co/Cu thin films and multilayer structures (MLS) having different layer thicknesses have been characterized utilizing X-ray diffraction (XRD), magnetooptical Kerr effect (MOKE), and resistivity techniques. The structural studies show distinctive crystal structures for different sublayer thicknesses. The Co (300 Å) single layer film is amorphous, while Cu (300 Å) film is nanocrystalline in nature. The average particle size is found to decrease as the number of interface increases. The corresponding magnetic and resistivity measurements show an increase in saturation field and resistivity as a result of an enhanced anisotropy. However, coercivity decreases with a reduction in average particle size. The results conclude that these properties are greatly influenced by various microstructural parameters such as layer thickness, number of bilayers, and the quality of interfaces molded under different growth conditions.