Sorption Diffusion Method Research Articles

Impact of Polyamide Surface Preparation on the Formation of Mixed CdS-CdTe Layers

CdTe-CdS layers were formed on polyamide (PA) 6 films with different surface modifications using the sorption-diffusion method. Part of the samples of the PA films was boiled in distilled water for 2 h and the other ones were stored in concentrated acetic acid at 20 °C for 0.5 h. After this stage, all the PA 6 films were chalcogenized at 20 °C for 1 or 5 h using an acidified 0.1 mol/L solution of K2TeS4O6. Then, the chalcogenized samples were treated with a 0.1 mol/L solution of cadmium acetate at 70, 80 or 90 °C for 10 min. The elemental and phase composition and the morphological and optical properties of the obtained films were determined. XRD analysis showed that cadmium chalcogenide layers consist of four phases: hexagonal CdTe, orthorhombic CdS, rhombohedral Te and orthorhombic S18. The average crystallite size among the obtained layers was very similar and was in the range of 36–42 nm. The concentrations of cadmium, sulfur and tellurium in the layers on PA 6 and the optical properties of the CdTe-CdS layers were dependent on the method of preparation of the polyamide film, the duration of chalcogenization and the temperature of the Cd(CH3COO)2 solution.

Formation and properties of mixed copper sulfide (CuxS) layers on polypropylene

The sorption-diffusion method was used to obtain nonstoichiometric copper sulfide layers on polypropylene. Copper sulfide layers consisted of monoclinic structures chalcocite Cu2S and djurleite Cu1.8S. This multiphase composition of obtained thin layers was confirmed by X-ray diffraction spectroscopy. The surface morphology of layers was studied by SEM micrographs and the surface roughness was calculated from AFM data. The value for the direct bandgap for the CuxS thin layers approximately equals 2.53 eV. The changes in mechanical properties (tensile strength analysis) of polypropylene films through the CuxS layer deposition process were investigated.

The structure of PA-Se-S-Cd composite materials probed with FTIR spectroscopy

Composite organic-inorganic functional materials are of significant importance in various applications of science and technology. In this work, PA-Se-S and PA-Se-S-Cd composite materials obtained by employing the sorption-diffusion method are discussed. A single precursor – K2SeS2O6 – was used as the source of both sulfur and selenium. In the aqueous solution, SeS2O62− and its decomposition products diffused into the polymer where they reacted with Cd2+ ions so that to form cadmium chalcogenide particles.Fourier-transform infrared (FTIR) spectroscopy was used to characterize the interactions between polyamide 6 and inorganic constituents, namely, K2SeS2O6, CdS and CdSe. The spectral behavior of amide I, II, A and B bands evidenced the competing formation of complex bonding structures based on the formation of covalent, electrostatic and hydrogen bonding between the PA 6 amide (NHCO) groups and the inorganic constituents. The number and the type of the formed bonds depend on the polyamide 6 exposure time in the K2SeS2O6 precursor solution. Such a complex interaction induces obvious conformational changes of the polyamide 6 chains. A possible bonding mechanism has been proposed to explain the observed spectral phenomena.

Formation of copper sulfides on polypropylene matrix using various reducing agents

Layers of copper sulfides, CuxS, on the surface of a polypropylene film were formed by the sorption–diffusion method using two reducing agents – hydroquinone and hydroxylamine sulfate. The formed copper sulfide layers were investigated by UV/VIS, X-ray diffraction (XRD) and water contact angle measurements (WCA). The investigations confirmed that a layer of nonstoichiometric copper sulfide was formed on the surface of the polypropylene film. The water contact angle measurements revealed the change in adhesive properties of the samples after each treatment stage.

Higher polythionic acids – the precursors for formation of thallium sulphide layers on polyethylene surface

The method of thallium sulphide thin films deposition on low density polyethylene (LDPE), based on applying solutions of higher polythionic acids (H2SnO6, n = 21, 33, 45), was developed and investigated. The concentration of sulphur in the LDPE film increases with the increase of temperature of higher polythionic acid solution and its sulphurity, as well as the duration of retention of LDPE in its solution is prolonged. The sulphur concentration in the PE film under the same duration of sulphurisation and repetition of treatment cycles insignificantly changes. When the sulphurised LDPE was treated with a thallium Tl(I) salt solution, sulphur present in the polymer reacts with thallium ions and the layers of thallium sulphides, TlxSy, of different composition are formed. The stoichiometric composition of the layer changes from Tl0.1S to Tl2.6S. The amount of thallium increases in the sulphide layers when the number of the cycles of LDPE sulphurisation in the H2S33O6 solution and treatment of sulphurised polymer with the Tl(I) salt solution is increased. The stoichiometric composition of TlxSy coats of one treatment cycle samples changes from Tl0.5S to Tl1.1S. The X-ray diffraction analysis of the polyethylene, treated with the solution of higher polythionic acid, H2S33O6, and then with the Tl(I) salt solution, confirmed the premise that on the LDPE surface the layers of thallium sulphides, TlxSy, were formed. Five phases of thallium sulphides were identified: TlS, Tl2S, Tl2S2, Tl4S3 and Tl2S5. The TlS phase prevailed in diffractograms. The chemical and phase composition of the TlxSy layers surface (up to 1 nm depth) is identified by X-ray photo-electronic spectroscopy analysis. The analysis data confirmed that the compounds of TlS, Tl2S, Tl2SO4, Tl(OH)3, S8 and Tl2O3 were formed on the surface of the layers. The morphology of thallium sulphide layers and the mechanism of their formation are determined by means of scanning atomic force and electronic microscopy. Two processes take place during the formation of the layer: desorption of sulphur and reaction of thallium ions from the thallium(I) salt solution with sulphur present on the LDPE surface. The layer of thallium sulphides is formed on the surface of the sulphur layer. Deposition of thallium sulpfide films from the solution of higher polythionic acid on the LDPE films is not homogeneous, it has the separated island type morphology. The identified regularities let purposively choose the conditions for sulphurisation of LDPE films by using the solution of higher polythionic acid as the agent of polymer sulphurisation in order to compose the layers of thallium sulphides, TlxSy, of the desired chemical and phasic composition on the surface of this polymer by means of the sorption–diffusion method.

Modification of polyamide films by semiconductive and conductive copper selenide–copper sulfide layers

Modification of the surface of polyamide 6 (PA) films by semiconductive and electrically conductive layers of mixed copper selenide–copper sulfide, CuxSe–CuyS, was performed using the sorption–diffusion method and the water solutions of potassium selenopentathionate, K2SeS4O6, as the precursor of polymer chalcogeniumization. Selenopentathionate anions containing divalent selenium and sulfur atoms of low oxidation state,–O3S-S-Se-S-SO3–, are sorbed-diffused into PA films if they are treated with selenopentathionate solutions. CuxSe–CuyS layers form on the surface of a PA (polyamide 6) film when a chalcogeniumized polymer is treated with a water solution of copper(II/I) salt: the anions of selenopentathionate react with copper ions. The concentration of sulfur, selenium and copper increases with an increase of the concentration and temperature of a precursor solution and the duration of PA initial chalcogeniumization. The formed layers were characterized for chemical composition, electrical and physical properties. The percentage amounts of selenium, sulfur and copper in CuxSe–CuyS layers on PA films increase with polymer chalcogeniumization time. The X–ray diffraction (XRD) pattern study of CuxSe–CuyS layers showed that they are polycrystalline in nature. The six phases of copper selenides – Cu2Se, CuSe2, CuSe2, Cu3Se2, berzellianite Cu2-xSe and bellidoite Cu2Se, also the four phases of copper sulfides – monoclinic djurleite, Cu1.9375Se, cubic digenite, Cu1.8S, orthorhombic chalcocite, Cu2S, and orthohrombic anilite, Cu1.75S, have been identified. With an increase of the concentration and temperature of the precursor solution and the duration of PA treatment the highest concentration of conductive copper selenides is reached and the composition of CuxSe phases changes in the direction of a decrease of x. XPS results confirmed the formation of copper selenides–copper sulfides layers on the surface of PA. The regularities established enable formation of CuxSe–CuyS layers of the desirable composition and conductivity. Studies by the method of atomic force microscopy (AFM) showed that depending on the conditions (duration of chalcogeniumization, concentration and temperature) of the PA initial treatment in the K2SeS4O6 solution (under the same “copperizing” conditions), the formation of copper chalcogenide layers proceeds irregularly in the form of islands which grow into larger agglomerates. The surface of the layer is uneven, rather rough.

Potassium selenotrithionate – the precursor for formation of semiconductive and conductive copper selenide layers on polyamide surface

Semiconducting and electrically conductive layers of copper selenide, CuxSey, on the polyamide 6 (PA) surface were formed using the sorption–diffusion method and the water solutions of potassium selenotrithionate, K2SeS2O6, as the precursor of polymer seleniumization. Selenotrithionate anions containing divalent selenium atoms of low oxidation state, –O3S-Se-SO3–, are sorbed-diffused into PA films if they are treated with selenotrithionate solutions. The concentration of sorbed selenotrithionate increases with an increase of the temperature and concentration of the precursor solution and the duration of PA treatment. CuxSey layers are formed on the surface of a PA film when a chalcogenized polymer is treated with the water solution of copper(II/I) salt: the anions of selenotrithionate react with copper ions. The concentration of copper increases with increasing the concentration and temperature of the precursor solution and the duration of PA initial chalcogenization. The formed layers were characterized for chemical composition, electrical and physical properties. The percentage amounts of selenium and copper in CuxSey layers on PA films with polymer seleniumization time changed as follows: Se from 51.61 to 69.46% and Cu from 48.39 to 30.54%. The most uniform thin layer of CuxSey formed on the polyamide film being seleniumized for 2.5 h was observed by scanning electron microscopy (SEM). The thickness of CuxSey layers depends on polymer seleniumization time and changed in an interval of 0.98–3.2 μm. The X-ray diffraction (XRD) pattern study of CuxSey layers showed that they are polycrystalline in nature; six phases of copper selenides Cu2Se (27-1131), CuSe2 (74-280), CuSe2 (18-453), Cu3Se2 (72-1421) and the phases of berzellianite Cu2-xSe (6-680) and of bellidoite Cu2Se (29-575) were identified. The XPS results confirmed the formation of copper selenides layers on the surface of PA. The regularities established enable the formation of CuySey layers of a desirable composition and conductivity.

Formation of Cadmium Selenide Layers on the Polyamide Film Surface by Sorption-Diffusion Method

The layers containing cadmium selenide, CdxSe,were formed on the surface of semihydrophilic polymer – polyamide 6 (PA) using acidified 0.10 mol/dm3 solution of potassium selenotrithionate, K2SeS2O6,as precursor of selenium. The concentration of sorbed selenium (at 60 oC) increases with the increase of the duration of PA treatment in K2SeS2O6solution. The cadmium selenide containing layers are formed on the surface of PA after the treatment of seleniumized polymer with cadmium acetate, (Cd(CH3COO)2·2H2O, solution (60–80 oC):the anions SeS2O62– containing selenium atoms of low oxidation state react with the cadmium(II) ions. The conditions of a polymer initial seleniumization and of seleniumized PA treatment with cadmium acetate solution determine the concentration of cadmium and the composition of chalcogenide layer. The concentration of cadmium in the chalcogenide layer increases with the increase of initial chalcogenization duration only up to about 2 h and the temperature of selenotrithionate solution. The results of XPS and XRD confirmed the formation of cadmium selenide layers on the surface of PA. XRD patterns study of not earlier studied CdSe layers on PA showed their phase composition of two cadmium selenides phases – Zinc blende (cubic) CdSe,wurtzite (hexagonal) CdSe and cadmium(II) hydroxide, Cd(OH)2. Accordingly data of XRD and XPS analysis the macrostructure and composition ofCuSe layers depends on the conditions of these layers formation. The data determined enable formation of the layers of cadmium selenide on the surface of PA by thesorption-diffusion method using the solution of potassium selenotrithionate as a precursor of selenium.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5097

Deposition, structure and properties of polyamide–CdSe–CdS composite material using sorption–diffusion method

Polyamide (PA) incorporated CdSe–CdS films were deposited using sorption–diffusion method. A single precursor – K2SeS2O6 was used as both sulfur and selenium source. In aqueous solution, SeS2O62− diffused into the polymer where it reacted with Cd2+ ions to form cadmium chalcogenide particles. Crystallinity of the composite material was analyzed via XRD and both CdSe and CdS were detected within the material at all deposition conditions of temperature and SeS2O62− – chalcogenization – exposure time. A complex surface speciation was obtained using XPS analysis. Formation of the protonated amide species was observed in combination with the adsorbed SO42− on the surface of the polymer confirming that SeS2O62− and its decomposition products hydrolyzed to form cadmium chalcogenides and H2SO4. A significant red shift in UV–vis spectrum was observed with the increasing chalcogenization time of PA, whereas Cd2+ solution temperature had very little effect on the apparent thickness and the optical properties of the composite materials. SEM surface analysis revealed sub-micron particles deposited on top of the PA–CdSe–CdS composite materials in continuous overlapping films, showing a possible dual crystal growth mechanism.

Comparison characterization of copper selenide thin layers prepared on polyamide 6 films by sorption-diffusion method

Abstract Some earlier synthesized copper selenide (Cux Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K2SeS2O6) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cux Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cux Se layers showed their phase composition of six copper selenides: Cu2Se, two phases of CuSe2, Cu3Se2, berzellianite, Cu2-x Se, and bellidoite Cu2Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the CuxSe layers depend on the conditions of formation of these layers.

Comparison of Telluropentathionates as Precursors for the Formation of Semiconductive Copper Chalcogenide Layers

The processes of obtaining semiconductive and electrically conductive layers of mixed copper chalcogenides CuxS–CuyTe by the sorption-diffusion method on polyamide 6 using solutions of potassium and sodium telluropentathionates, K2TeS4O6 and Na2TeS4O6, and of telluropentathionic acid, H2TeS4O6, as precursors of chalcogens (Te and S) are compared. The concentration of sorbed chalcogens increases with the increase of the duration of treatment and concentration of precursor solution in cases of all precursors used. Copper chalcogenide layers are formed on the surface of polyamide after the treatment of chalcogenized polymer with Cu(II/I) salt solution. The concentration of copper in the layer increases with the increase of initial chalcogenization duration. XRD spectra of PA films treated for different time with solutions of telluropentathionates and then with Cu(II/I) salt solution showed the maxima characteristic of the copper sulfide and copper telluride phases, tellurium sulfide TeS7 and of elemental tellurium. Six copper sulfide phases, chalcocite, Cu2S, djurleite, Cu1.9375S, anilite, Cu1.75S, digenite, Cu1.80S, villamanite, CuS2, covelite, CuS, three copper telluride phases Cu4Te3, Cu1.85Te, rickardite, Cu7Te5, and tellurium sulfide TeS7 were identified in the layers formed using (0.025 – 0.1) mol/dm3 solutions of potassium telluropentathionate. Three phases of copper tellurides, tetragonal Cu3.18Te2, hexagonal Cu2Te and orthorhombic vulcanite, CuTe, were found in the films on PA surface formed using sodium telluropentathionate solutions, among them four phases of copper sulfides such as orthorhombic anilite, Cu7S4, monoclinic djurleite, Cu1.9375S, geerite, Cu1.6S, orthorhombic digenite, Cu1.8S, and tellurium sulfide TeS7; the Cu–Te–S layers formed using H2TeS4O6 solution have binary phases such as chalcocite, Cu2S, djurleite, Cu1.9375S, anilite, Cu1.75S, digenite, Cu1.80S, copper telluride Cu1.85Te, elemental tallurium and tellurium sulfide TeS7. The phase composition of layers changes depending on the nature of telluropentathionate used for PA chalcogenization and conditions of treatment in precursor’ solutions. The value of electrical sheet resistance of chalcogenide layers formed using (0.05 – 0.1) mol/dm3 K2TeS4O6 solutions varies from 256 kW/cm2 to 1.6 kW/cm2 and of those formed using Na2TeS4O6 solutions – from 3.14·103 kW/cm2 to ~1.34 kW/cm2; the use of H2TeS4O6 as precursor leads to the formation of electrically conductive CuxS–CuyTe layers with electrical resistance in the range of (4.34·103 – 1.2) kW/cm2; the sheet resistance depends on the conditions of PA interaction with initial chalcogenization solutions.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1909

Formation of CuxS Layers on Polypropylene Sulfurized by Molten Sulfur

The processes of formation of electrically conductive layers of copper sulfides CuxS by the sorption-diffusion method on polypropylene (PP) using molten sulfur as sulfurizing agent was investigated. The amount of sorbed sulfur increased with the increase of the duration of treatment. Copper sulfide layers were formed on the surface of polypropylene after the treatment of sulfurized polymer with Cu(II/I) salt solution. The amount of copper sulfide in layer increased with the increase of treatment duration in copper salt solution. XRD spectra of PP films treated for 3 min with molten sulfur and then with Cu(II/I) salt solution for the different time showed that the copper sulfide phases, mostly digenite, Cu2-xS and a-chalcocite, Cu2S were formed in the layers. Electromotive force measurement results confirmed the composition of formed CuxS layers on PP. The phase composition of layers also changed after the annealing. The value of electrical resistance of copper sulfide layers on PP varied from 20 W/cm2 to 80 W/cm2 and after annealing at 80 °C - in the interval of 10 W/cm2 - 60 W/cm2.http://dx.doi.org/10.5755/j01.ms.17.4.776

Comparison of Polythionates as Precursors for the Formation of Thallium Sulfide Layers

The processes of obtaining layers of thallium, sulfides, Tl x S y , by the sorption-diffusion method on polyamide 6 using solutions of lower polythionates - sodium trithionate and tetrathionate, Na 2 S 3 O 6 , Na 2 S 4 O 6 , potassium pentathionate, K 2 S 5 O 6 , and of dodecathionic acid, H 2 S 12 O 6 , as precursors of sulfur are compared. The concentration of sorbed sulfur increases with increasing the duration of treatment, the concentration and temperature of precursor solution. It rather significantly also depends on the nature - sulfurity of polythionate, i. e. on the number of sulfur atoms in the polythionate anion: effectiveness of sulfurization using solutions of dodecathionic acid is significantly higher than that of lower polythionates. Thallium sulfide layers are formed on the surface of polyamide after the treatment of sulfurized polymer with Tl(I) salt solution. The concentration of thallium in the layer increases with the increase of initial sulfurization duration and in case of H 2 S 12 O 6 solution used - on the temperature of this process. The results of X-ray diffraction analysis confirmed the formation of thallium sulfide layers in the surface of polyamide 6. The phase composition of layer changes depending on the conditions of initial treatment in a H 2 S 12 O 6 solution. Five thallium sulfide phases, two forms of TlS, Tl 2 S 2 , Tl 4 S 3 and Tl 2 S 5 were identified in the composition of the layers treated for different time with a solution of dodecathionic acid at the temperature of 20 °C and 30 °C and then with Tl(I) salt solution by X-ray diffraction but the maxima of TlS and Tl 2 S 5 phases predominate in the diffractograms. http://dx.doi.org/10.5755/j01.ms.17.4.774

Optical, XPS and XRD Studies of Semiconducting Copper Sulfide Layers on a Polyamide Film

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption‐diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅ dm−3 K2S5O6 solutions and acidified with HCl (0.1 mol⋅ dm−3) at 20∘C. After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band‐gap semiconductors. The values of Ebg are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with Ar+ ions. It has been established by the XRD method that, beside Cu2S, the layer contains Cu1.9375S as well. For PA 6 initially sulfured 4 h, grain size for chalcocite, Cu2S, was ∼35.60 nm and for djurleite, Cu1.9375S, it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 Ω/cm2.

Formation and characterization of conductive thin layers of copper sulfide (CuxS) on the surface of polyethylene and polyamide by the use of higher polythionic acids

Layers of copper sulfide of varying composition and properties are formed on the surface of polyethylene and polyamide by a sorption–diffusion method using solutions of higher polythionic acids, H2SnO6. The concentration of sulfur adsorbed–diffused into PE and PA depends on the degree of the acid sulfurity, n, the temperature of the solution and the period of the polymer treatment. The amount of copper in a sulfide (CuxS) layer formed after the sulfured polymer treatment with a solution of Cu(I–II) salt is strongly dependent on the concentration of sulfur in the PE and PA. By the chemical analysis of the obtained sulfide layers was determined that a value of x in the CuxS layers varies in the interval 1 < x < 2. The microscopic investigation of transverse sections of PE and PA samples with copper sulfide layers showed that the major part of copper sulfide is in the surface matrix of the polymer. X-ray diffraction studies of the CuxS layers obtained seven phases: with x = 2 (chalcocite), 1.9375 (djurleite), 1.8 (digenite), 1.75 (anilite), 1.12 (yarrowite), 1.06 (talnakhite) and 1 (covellite). The measurements of the electrical conductance of CuxS layers (0.1–4 S cm−2) showed that its value greatly depends on the conditions of PE and PA interaction with H2SnO6 and of further interaction with Cu(I–II) salt solution, on the chemical and phase composition of the layer.

Chemical deposition of copper sulfide films in the surface of polyamide by the use of higher polythionic acids

Films of copper sulfides of varying composition are formed in a surface matrix of polyamide by a sorption–diffusion method using solutions of higher polythionic acids, H2S n O6 (n>6), as sulfuring agents. A film of nonstoichiometric Cu x S (x=1.06-1.95) is obtained when the sulfured polyamide is treated with a solution of Cu(I-II) salt. The value of x in Cu x S decreases with the prolongation of the period of polyamide sulfuration in the H2S n O6 solution and increases with the prolongation of the period of sulfured polyamide interaction with the copper salt solution. The films obtained are formed from two main phases: yarrowite (Cu1.12S) and anilite (Cu1.75S). Depending on the polyamide sulfuration and the sulfured polyamide interaction with a solution of Cu(I-II) salt conditions, Cu x S films on polyamide of different electrical conductivity were obtained. The sulfide with a composition close to CuS has the highest electrical conductivity.