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113 results on '"Fahmi, Amir"'

101. Electrospun Smart Hybrid Nanofibers for Multifaceted Applications.

Author

Nirwan, Viraj P., Amarjargal, Altangerel, Hengsbach, Rebecca, and Fahmi, Amir

Subjects
*TECHNOLOGICAL innovations, *NANOSTRUCTURED materials, *ELECTROTEXTILES, *HYBRID materials, *NANOFIBERS, *SMART materials
Abstract

Smart electrospun hybrid nanofibers represent a cutting‐edge class of functional nanostructured materials with unique collective properties. This review aims to provide a comprehensive overview of the applications of smart electrospun hybrid nanofibers in the fields of energy, catalysis, and biomedicine. Electrospinning is a powerful tool to fabricate different types of nanofibers’ morphologies with precise control over structure and compositions. Through the incorporation of various functional components, such as nanoparticles, nanomoieties, and biomolecules, into the (co)polymer matrix, nanofibers can be tailored into smart hybrid materials exhibiting responsiveness to external stimuli such as temperature, pH, or light among others. Herein recent advancements in fabrication strategies for electrospun smart hybrid nanofibers are discussed, focusing on different electrospinning tools aimed at tailoring and developing smart hybrid nanofibers. These strategies include surface functionalization, doping, and templating, which enable fine‐tuning of mechanical strength, conductivity, and biocompatibility. The review explores the challenges and recent progress in the development of smart hybrid nanofibers. Issues such as scalability, reproducibility, biocompatibility, and environmental sustainability are identified as key for improvement. Furthermore, the applications of smart nanofibers in biomedicine, environment, energy storage, and smart textiles underscore their potential to address the challenges in development of nanostructured materials for emerging technologies. [ABSTRACT FROM AUTHOR]

Published
2024
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102. Directing the SelfAssembly of Mesostructured Hybrid Materials: Effect of Polymer Concentration and Solvent Type

Author

Pietsch, Torsten, Metwalli, Ezzeldin, Roth, Stephan Volker, Gebhardt, Ronald, Gindy, Nabil, MüllerBuschbaum, Peter, and Fahmi, Amir

Abstract

Herein we explore the possibility to control the fabrication of nonequilibrium nanopatterns of spincoated organicinorganic hybrid materials based on diblock copolymers and metal nanoparticles in thin films. It is demonstrated that the type of solvent and the initial solution concentration, among other factors, can serve as tools to direct the morphology of spincoated thin films. The driving forces leading to the pattern formation are reviewed with respect to these parameters—type of solvents and polymer concentration. As a result welldefined surface patterns of functional hybrid materials are obtained. Moreover, the same tools used to direct the pattern formation can be applied to gain control over the particle size and size distribution.

Published
2009
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104. Ring and Disk-Like CdSe Nanoparticles Stabilized with Copolymers

Author

Fahmi, Amir Wagih, Oertel, Ulrich, Steinert, Volker, Froeck, Christian, and Stamm, Manfred

Abstract

CdSe nanoparticles stabilized with the amphiphilic diblock copolymer polystyrene-block-poly(4-vinylpyridine) were spread from toluene dispersion on the water surface. Monolayers could be transferred onto solid substrates using the Langmuir-Blodgett technique. By means of atomic force and scanning electron microscopy highly symmetric ring and disk-like structures with diameters ranging between 150 nm and 1200 nm were observed. AFM image of a mixed monolayer of copolymer 12 and CdSe nanoparticles stabilized with polystyrene-block-poly(4-vinylpyridine).

Published
2003
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105. The Effect of a Polyester Nanofibrous Membrane with a Fibrin-Platelet Lysate Coating on Keratinocytes and Endothelial Cells in a Co-Culture System.

Author

Blanquer, Andreu, Musilkova, Jana, Filova, Elena, Taborska, Johanka, Brynda, Eduard, Riedel, Tomas, Klapstova, Andrea, Jencova, Vera, Mullerova, Jana, Kostakova, Eva Kuzelova, Prochazkova, Renata, Bacakova, Lucie, and Fahmi, Amir

Subjects
ENDOTHELIAL cells, KERATINOCYTES, KERATINOCYTE differentiation, CELL migration, POLYESTERS, DASATINIB, POLYCAPROLACTONE
Abstract

Chronic wounds affect millions of patients worldwide, and it is estimated that this number will increase steadily in the future due to population ageing. The research of new therapeutic approaches to wound healing includes the development of nanofibrous meshes and the use of platelet lysate (PL) to stimulate skin regeneration. This study considers a combination of a degradable electrospun nanofibrous blend of poly(L-lactide-co-ε-caprolactone) and poly(ε-caprolactone) (PLCL/PCL) membranes (NF) and fibrin loaded with various concentrations of PL aimed at the development of bioactive skin wound healing dressings. The cytocompatibility of the NF membranes, as well as the effect of PL, was evaluated in both monocultures and co-cultures of human keratinocytes and human endothelial cells. We determined that the keratinocytes were able to adhere on all the membranes, and their increased proliferation and differentiation was observed on the membranes that contained fibrin with at least 50% of PL (Fbg + PL) after 14 days. With respect to the co-culture experiments, the membranes with fibrin with 20% of PL were observed to enhance the metabolic activity of endothelial cells and their migration, and the proliferation and differentiation of keratinocytes. The results suggest that the newly developed NF combined with fibrin and PL, described in the study, provides a promising dressing for chronic wound healing purposes. [ABSTRACT FROM AUTHOR]

Published
2021
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106. Polyamide 66 microspheres metallised with in situ synthesised gold nanoparticles for a catalytic application

Author

Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, Fahmi, Amir, Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, and Fahmi, Amir

Abstract

A simple concept is proposed to metallise polyamide 66 (PA66) spherulite structures with in situ synthesised gold nanoparticles (Au NPs) using a wet chemical method. This cost-effective approach, applied to produce a PA66/Au NP hybrid material, offers the advantages of controlling the nanoparticle size, the size distribution and the organic- inorganic interactions. These are the key factors that have to be controlled to construct consistent Au nanostructures which are essential for producing the catalytic activities of interest. The hybrid materials obtained are characterised by means of scanning electron microscopy, transmission electron microscopy, attenuated total reflection-Fourier transform infrared spectrometry and X-ray diffraction spectrometry. The results show that PA66 microspheres obtained via the crystallisation process are coated with Au NPs of 13 nm in size. It was found that controlling the metal coordination is the key parameter to template the Au NPs on the spherulite surfaces. The preparation processes and the key factors leading to the formation of PA66 spherulites coated with Au NPs are discussed. Moreover, the efficiency of the coated spherulites as a potential catalyst is proved by demonstrating the reduction of methylene blue via UV-visible spectrometry.

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107. Polyamide 66 microspheres metallised with in situ synthesised gold nanoparticles for a catalytic application

Author

Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, Fahmi, Amir, Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, and Fahmi, Amir

Abstract

A simple concept is proposed to metallise polyamide 66 (PA66) spherulite structures with in situ synthesised gold nanoparticles (Au NPs) using a wet chemical method. This cost-effective approach, applied to produce a PA66/Au NP hybrid material, offers the advantages of controlling the nanoparticle size, the size distribution and the organic- inorganic interactions. These are the key factors that have to be controlled to construct consistent Au nanostructures which are essential for producing the catalytic activities of interest. The hybrid materials obtained are characterised by means of scanning electron microscopy, transmission electron microscopy, attenuated total reflection-Fourier transform infrared spectrometry and X-ray diffraction spectrometry. The results show that PA66 microspheres obtained via the crystallisation process are coated with Au NPs of 13 nm in size. It was found that controlling the metal coordination is the key parameter to template the Au NPs on the spherulite surfaces. The preparation processes and the key factors leading to the formation of PA66 spherulites coated with Au NPs are discussed. Moreover, the efficiency of the coated spherulites as a potential catalyst is proved by demonstrating the reduction of methylene blue via UV-visible spectrometry.

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108. Polyamide 66 microspheres metallised with in situ synthesised gold nanoparticles for a catalytic application

Author

Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, Fahmi, Amir, Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, and Fahmi, Amir

Abstract

A simple concept is proposed to metallise polyamide 66 (PA66) spherulite structures with in situ synthesised gold nanoparticles (Au NPs) using a wet chemical method. This cost-effective approach, applied to produce a PA66/Au NP hybrid material, offers the advantages of controlling the nanoparticle size, the size distribution and the organic- inorganic interactions. These are the key factors that have to be controlled to construct consistent Au nanostructures which are essential for producing the catalytic activities of interest. The hybrid materials obtained are characterised by means of scanning electron microscopy, transmission electron microscopy, attenuated total reflection-Fourier transform infrared spectrometry and X-ray diffraction spectrometry. The results show that PA66 microspheres obtained via the crystallisation process are coated with Au NPs of 13 nm in size. It was found that controlling the metal coordination is the key parameter to template the Au NPs on the spherulite surfaces. The preparation processes and the key factors leading to the formation of PA66 spherulites coated with Au NPs are discussed. Moreover, the efficiency of the coated spherulites as a potential catalyst is proved by demonstrating the reduction of methylene blue via UV-visible spectrometry.

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109. Polyamide 66 microspheres metallised with in situ synthesised gold nanoparticles for a catalytic application

Author

Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, Fahmi, Amir, Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, and Fahmi, Amir

Abstract

A simple concept is proposed to metallise polyamide 66 (PA66) spherulite structures with in situ synthesised gold nanoparticles (Au NPs) using a wet chemical method. This cost-effective approach, applied to produce a PA66/Au NP hybrid material, offers the advantages of controlling the nanoparticle size, the size distribution and the organic- inorganic interactions. These are the key factors that have to be controlled to construct consistent Au nanostructures which are essential for producing the catalytic activities of interest. The hybrid materials obtained are characterised by means of scanning electron microscopy, transmission electron microscopy, attenuated total reflection-Fourier transform infrared spectrometry and X-ray diffraction spectrometry. The results show that PA66 microspheres obtained via the crystallisation process are coated with Au NPs of 13 nm in size. It was found that controlling the metal coordination is the key parameter to template the Au NPs on the spherulite surfaces. The preparation processes and the key factors leading to the formation of PA66 spherulites coated with Au NPs are discussed. Moreover, the efficiency of the coated spherulites as a potential catalyst is proved by demonstrating the reduction of methylene blue via UV-visible spectrometry.

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110. Polyamide 66 microspheres metallised with in situ synthesised gold nanoparticles for a catalytic application

Author

Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, Fahmi, Amir, Cheval, Nicolas, Gindy, Nabil, Flowkes, Clifford, and Fahmi, Amir

Abstract

A simple concept is proposed to metallise polyamide 66 (PA66) spherulite structures with in situ synthesised gold nanoparticles (Au NPs) using a wet chemical method. This cost-effective approach, applied to produce a PA66/Au NP hybrid material, offers the advantages of controlling the nanoparticle size, the size distribution and the organic- inorganic interactions. These are the key factors that have to be controlled to construct consistent Au nanostructures which are essential for producing the catalytic activities of interest. The hybrid materials obtained are characterised by means of scanning electron microscopy, transmission electron microscopy, attenuated total reflection-Fourier transform infrared spectrometry and X-ray diffraction spectrometry. The results show that PA66 microspheres obtained via the crystallisation process are coated with Au NPs of 13 nm in size. It was found that controlling the metal coordination is the key parameter to template the Au NPs on the spherulite surfaces. The preparation processes and the key factors leading to the formation of PA66 spherulites coated with Au NPs are discussed. Moreover, the efficiency of the coated spherulites as a potential catalyst is proved by demonstrating the reduction of methylene blue via UV-visible spectrometry.

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111. Modified Silica Sol Coatings for Surface Enhancement of Leather.

Author

Mahltig, Boris, Vossebein, Lutz, Ehrmann, Andrea, Cheval, Nicolas, and Fahmi, Amir

Subjects
*SILICA, *SOL-gel processes, *LEATHER, *SURFACE coatings, *SURFACE chemistry, *HYDROLYSIS, *FLUORINATION, *SCANNING electron microscopy
Abstract

The presented study reports on differently modified silica sols for coating applications on leather. Silica sols are prepared by acidic hydrolysis of tetraethoxysilane and modified by silane compounds with fluorinated and non-fluorinated alkyl groups. In contrast to many earlier investigations regarding sol-gel applications on leather, no acrylic resin is used together with the silica sols when applying on leather. The modified silica particles are supposed to aggregate after application, forming thus a modified silica coating on the leather substrate. Scanning electron microscopy investigation shows that the applied silica coatings do not fill up or close the pores of the leather substrate. However, even if the pores of the leather are not sealed by this sol-gel coating, an improvement of the water repellent and oil repellent properties of the leather substrates are observed. These improved properties of leather by application of modified silica sols can provide the opportunity to develop sol-gel products for leather materials present in daily life [ABSTRACT FROM AUTHOR]

Published
2012

112. Spatially correlated metallic nanostructures on self-assembled diblock copolymer templates.

Author

Fahmi AW and Stamm M

Abstract

Polymeric complexes based on diblock copolymers (polystyrene-block-4-vinylpyridine) hydrogen bonded with pentadecylphenol self-assemble under oscillatory shear flow into a highly ordered lamellar structure (Ikkala et al. Science 2002). Microtomed films of the lamellar structure form an array of "nanosheets"following immersion in methanol. We have exploited this nanosheet array as an extremely effective template to direct the spatial organisation of metallic (Pd) nanoclusters. The electroless deposition metal on the nanotemplates leads to morphologically complex nanostructured metallic films which were observed using atomic force microscopy and scanning electron microscopy.

Published
2005
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113. Electrochemical nucleation of gold nanoparticles in a polymer film at a liquid-liquid interface.

Author

Knake R, Fahmi AW, Tofail SA, Clohessy J, Mihov M, and Cunnane VJ

Abstract

Simultaneous nucleation of gold nanoparticles and polymerization of tyramine has been carried out at an immiscible electrolyte interface. By transferring the gold ion of tetraoctylammoniumtetracloroaurate (TOAAuCl(4)) from the organic to the aqueous phase, a fast homogeneous electron transfer from the tyramine monomer reduces the gold ion. Electropolymerization then proceeds, and gold nanoparticles form. The newly formed nanoparticles act as nucleation sites for the deposition of the oligomers/polymer (and possibly vice versa). This results in gold nanoparticles stabilized in a polytyramine matrix. The size of the nanoparticles is controlled by the concentration of oligomers/polymer in solution. The polymer nanoparticle composite film was analyzed with TEM, XPS, and AFM.

Published
2005
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