Navegando por Autor "Naeem, Muhammad"

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Novel antibacterial silver coating on PET fabric assisted with hollow-cathode glow discharge
(Wiley, 2020-07-30) Nascimento, Rubens Maribondo do; Naeem, Muhammad; Felipe, M. B. M. C.; Medeiros, Silvia Regina Batistuzzo de; Costa, Thércio Henrique de Carvalho; Libório, Maxwell Santana; Alves Júnior, Clodomiro; Nascimento, Igor Oliveira; Sousa, R. R. M.; Feitor, Michelle Cequeira
The silver-coated fabrics are of much importance because of their outstanding antibacterial features and are useable in several medical and hygienic applications. The silver deposition on fabrics by conventional techniques is not feasible because of their high processing cost, long processing duration, complex equipment, and multiple steps processing (nanoparticle synthesis and subsequent deposition on fabrics). In this novel study, the antibacterial silver coating is deposited by using a hollow cathode discharge (HCD) capable of generating high-density plasma, and thus it exhibits high-efficiency processing. The silver is deposited on woven and non-woven PET fabrics for various treatment times (10-60 minutes), and their antibacterial performance against E. coli and S. aureus bacterial is tested. The XRD results verified the deposition of silver with (111) preferred orientation, while SEM analysis depicted the uniform/ homogeneous deposition of silver particles. The interfacial free energy of adhesion depicts that after the silver deposition on both fabrics, the surface is actively unfavorable for bacterial adhesion. The antibacterial test revealed that the silver-coated woven and non-woven PET fabrics exhibit exceptional antibacterial activity against E. coli and S. aureus bacteria. As the HCD technique is relatively cost-effective, no need for specific sputtering targets, eco-friendly, and require single-step processing for silver deposition. Thus the results are expected to be of remarkable importance to prepare silver-coated antibacterial fabrics useable in hospitals and other appropriate applications
Novel synthesis of copper oxide on fabric samples by cathodic cage plasma deposition
(Polymers for Advanced Technologies, 2019-11-11) Feitor, Michele Cequeira; Fernades, Fernanda; Rocha Filho, Edglay; Souza, Ivan; Nascimento, Igor; Sousa, Rômulo; Almeida, Edalmy; Costa, Thércio; Naeem, Muhammad; Iqbal, Javed
The fabrics with copper or copper oxide deposition are of considerable interest because of exceptional antibacterial properties, which are useable in medical, textiles, and hygiene applications. Unfortunately, the conventional techniques take long pro-cessing time, complex equipment, and combination of several processing steps (nano-particles synthesis and their deposition on fabrics). In this novel study, cathodic cage plasma deposition assisted with copper cathodic cage is used for the synthesis of the copper oxide on polyester and polyamide fabrics. For the enhancement of synthesis efficiency, the effect of cathodic cage lid thickness is also investigated. The samples are assessed by using scanning electron microscopy, elemental dispersive spectros-copy, and X‐ray photoelectron spectroscopy. It is found that using cathodic cage plasma deposition, fabrics can be successfully synthesized by the copper oxide with comparatively small treatment time, cost‐effectively, and environmentally friendly. Interestingly, cathodic cage plasma treatment is already proved to be working effec- tively on industrial scale; thus, it is predicted to be of noteworthy importance for fab- rics processing on large‐scale garments manufacturing and hospitals.
Surface modification of PET fabric by plasma pre-treatment for long-lasting permethrin deposition
(Wiley, 2020-05-18) Feitor, Michelle Cequeira; Badaro, Adair Divino da Silva; Libório, Maxwell Santana; Souza, Flaviane camara de; Sousa, Rômulo Ribeiro Magalhães; Santos, Rayane Saory Medeiros dos; Costa, Thércio Henrique de Carvalho; Naeem, Muhammad; Iqba, Javed
The mosquito-transmitted diseases are of serious concern and are affecting several millions of peoples worldwide. Instead of medication afterward the disease initiated, self-protection against the mosquito's is preferable, specifically in endemic areas. For this purpose, the permethrin coated clothing is a suitable choice to avoid mosquitos' bites. Unfortunately, the permethrin coating on fabrics is not long-lasting, and its laundering resistance is very low on hydrophobic fabric. In this study, the effect of plasma surface modification of PET fabric on the adhesion of permethrin and its laundering resistance are evaluated. The plasma processing is carried out in nitrogen, oxygen, and nitrogen–oxygen mixture plasma. The samples are analyzed using Fourier Transform Infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscope and chromatography. The results show that the oxygen plasma pre-treated samples exhibit the higher residual contents of permethrin after 60 wash cycles as compared with other gasses. Without plasma pre-treatment, the 95% loss, whereas the sample with oxygen plasma pre-treatment shows that only 22% loss of initial concentration of permethrin occurs after washing. This study shows that plasma pre-treatment is valuable to improve the absorption of permethrin in PET and its laundering-resistance. As plasma treatment is a cost-effective technique, it needs less processing time and eco-friendly, thus it is a great choice to deposit long-lasting permethrin coating by plasma pre-treatment, instead of conventional binding agents. Remarkably, the plasma treatment technique is a well-established and industrially acceptable technique, thus expected to be of noteworthy importance for insecticide garments manufacturers
Synthesis and characterization of ZnO/ZnAl2O4/ Zn2TiO4 composite films by AreO2 mixture hollow cathode glow discharge
(Elsevier, 2021) Feitor, Michelle Cequeira; Queiroz, José César Augusto de; Naeem, Muhammad; Azevedo Filho, João Batista; Libório, Maxwell Santana; Queiroz, M. G. O.; Sousa, R. R. M.; Melo, E. B.; Costa, Thércio Henrique de Carvalho
In this study, ZnO/ZnAl2O4/Zn2TiO4 composite nanostructured thin films are deposited assisted with hollow-cathode glow discharge (HCD). The films are deposited using various argon-oxygen gases mixture (0e50% O2), and its effect on film quality, optical and electrical properties is examined. Remarkably, instead of metallic targets, ZnO, TiO2, and Al2O3 powders filled in hollow-cathode are used for deposition, and thus no specific metallic targets are required in this technique. The deposited films consist of hexagonal wurtzite ZnO structure, ZnAl2O4, and Zn2TiO4 phases, and the crystalline size of films increases for higher oxygen contents. The thickness of films reduced by increasing oxygen contents, and all deposited films exhibit transmittance higher than 82%. The carrier concentration and mobility increase, whereas resistivity decreases when a higher amount of oxygen is added. This study shows that HCD can effectively synthesize the composite film with good optical and electrical properties. Additionally, the film’s properties and elemental composition can be tuned by changing the gas composition, and thus, no separate target metallic materials with the specific composition are required
Synthesis of Al-Doped ZnO films assisted with hollow-cathode glow discharge and their characterization
(Journal of Electronic Materials, 2021-02-19) Feitor, Michelle Cequeira; Queiroz, José César Augusto de; Naeem, Muhammad; Azevedo Filho, João Batista; Liborio, Maxwell Santana; Santos, E. J. C.; Sousa, R. R. M.; Costa, Thércio Henrique de Carvalho; Khan, Naveed H.
Transparent conductive oxides, such as aluminum-doped zinc oxide (AZO), are of substantial importance for use in a broad range of applications because of their excellent optical and electrical properties. AZO film can be deposited by using several conventional techniques, although they suffer from limitations such as long deposition time, high cost, and the requirement for complex deposition equipment. Here, we used hollow-cathode glow discharge, which produces a high-density plasma and achieves high deposition efficiency. Remarkably, instead of metallic target materials, we used Al2O3 and ZnO powders filled in the hollow cathode as a target, thus avoiding the need for specifically designed targets in this technique. The films were deposited using mixtures of argon and oxygen at various ratios (0% to 50% oxygen), to improve the film characteristics. The films deposited under all conditions exhibited hexagonal wurtzite ZnO structure, while the grain size increased with increasing oxygen content. The film was thick and porous when using low oxygen content, but became thin and dense with increasing oxygen content. The optical transmittance was found to be strongly dependent on the processing gases used, with the highest transmittance of 84% being attained when using 25% oxygen gas. The bandgap of the films lay between 3.27 eV and 3.33 eV. The highest carrier concentration and mobility were attained when using 25% oxygen, and the Hall resistivity decreased with increasing oxygen content. Besides the excellent transmittance and electrical properties of the deposited films, it is expected that the results of this study will be useful for solar cells and optoelectronic applications due to the relatively low cost of this technique and the lack of specific target requirements

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Navegando por Autor "Naeem, Muhammad"