Materials Physics and Chemistry

Fullerene-doped polyimide materials treated via the vacuum ultraviolet irradiation: Novel possible approach to create the structured relief

Natalia Kamanina — 2023-04-23

Among the various surface reliefs obtained by the modification of the nanostructured materials used for the orientation of the liquid crystal molecules or applied as the possible way to extend the optical limiting mechanisms, the vacuum ultraviolet irradiation can provoke the novel approach with the varied contact angle and can be recommended for use in the development of the light- and electro-addressable liquid crystal spatial light modulators, switchers, and limiters. The main accent in the current paper is connected with the study of an impact of the vacuum ultraviolet irradiation with the different wavelength and power densities on the fullerene-structured polyimide thin films. To support the proposed idea, the spectral measurements were carried out, the contact wetting angles of the structured surface were determined, and an atomic force microscopic analysis was performed. Based on the data obtained, it is proposed to effectively use such relief formed by the vacuum ultraviolet irradiation for the design of the modulators and converters of the laser radiation, some biomedicine devices and the solar cells as well where a liquid crystal mesophase is actively used as an electro-optical modulating layer. Some ideology of the current article is aimed that the polyimide materials, when irradiated in the vacuum ultraviolet, can perform a dual role, as a photo layer and as an orienting layer as well.

The influence of surface imperfections on phosphate coating performance of nodular cast iron substrates

Samuel A. Awe — 2023-08-21

The service performance of the nodular cast iron wheel hub was modelled by investigating the effect of surface morphology and characteristics on the phosphate coating size, morphology, and corrosion resistance properties of the zinc phosphate conversion coated cast iron substrates. The machined and unmachined surfaces as well as the coatings were examined by a scanning electron microscope coupled with an energy-dispersive X-ray spectrometer (SEM-EXD). The influence of the substratesâ€™ surface imperfections on the phosphate coating and the subsequent corrosion resistance was assessed and rated according to the standard procedures. Surface analysis of the machined and unmachined cast iron hubs reveals the existence of graphite and foreign material inclusions on the substrate surface that impact the phosphate coating properties and resistance to corrosion. The average phosphate coating crystal size is 1.74 Âµm and 2.58 Âµm for the unmachined and machined cast iron substrates, respectively. The corrosion resistance of the coated unmachined wheel hub surfaces was rated poor and disapproved based on the application requirements. The poor corrosion resistance was ascribed to the influence of the substratesâ€™ surface characteristics on the coating adhesion to the substrate. However, the cast surfaces should be properly shot-blasted to remove any adhere foreign materials on the as-cast skin to enhance the coating adhesion.

Investigation of poly (2-methyl imidazole co 1,4-butanediol diglycidyl ether) as a leveler for blind hole copper plating

Xiangjian Zeng — 2023-09-09

The current synthetic leveler agents are complex to operate, troublesome to purify, and low to pore filling rates. Herein, we report a new, simple, green, and inexpensive method for the synthesis of leveler agents and study their properties systematically. In acidic copper sulfate plating solutions, including polyethylene glycol (PEG), sodium 3,3â€™-dithiodipropane sulfonate (SPS), and chloride ions, the relation between leveler agents (dimethylimidazole and 1,4-butanediol diglycidyl ether) and the filling of blind holes have been investigated. The synthesized leveler agent was structurally characterized by infrared spectroscopy and gel chromatography tests. The plating containing the leveler agent passed plating tests as well as reliability tests and met PCB production requirements. The electrochemical behavior of the leveler agent was investigated using electrochemical tests. The X-ray diffractometer (XRD) was used to observe the differences in crystal orientation on the surface of the plated layers.

Adsorption studies of dye molecule on two-dimensional assembly of porphyrin using density functional theory

Rahul Suresh — 2023-10-24

Highly toxic dye molecules can be found in trace amounts in the treated effluent from several industrial wastes. A challenging research area of this decade is the dye treatment and adsorption from the effluents of these industries using low-cost alternative adsorbents. Recent studies have demonstrated the effectiveness of metal oxides and porous materials in the adsorption of dye, so we have taken into consideration an organic porous material made with metal free porphyrin. The adsorption of dye molecules on the surface of the porphyrin sheet is investigated. Porphyrin is an organic substance with several special properties. Density functional theory (DFT) is used to investigate the adsorption of charged and neutral dye, as well as complex heavy metal dye, on the surface of porphyrin sheets. Positive dye has a higher affinity for the adsorbent than negative dye, according to the data on adsorption; however, complex dye has a higher adsorption energy than the other dyes, which is consistent with the cohesive energy of the PS-dye complex. In the present work the adsorbing capacity of PS for different dye molecules is demonstrated by the topological analysis and DFT calculations on the electronic structure.