Samar Medda - Academia.edu (original) (raw)
Uploads
Papers by Samar Medda
Materials Advances, 2022
The present work describes the fabrication of functionalized mesoporous silica based antireflecti... more The present work describes the fabrication of functionalized mesoporous silica based antireflective-cum-hydrophobic coatings on textured solar cover glasses via a spray-coating technique exhibiting enhanced photo-current density.
Bulletin of Materials Science, 2008
ACS Applied Materials & Interfaces, 2011
The paper deals with the fabrication of solÀgel-derived superhydrophobic films on glass based on ... more The paper deals with the fabrication of solÀgel-derived superhydrophobic films on glass based on the macroscopic silica network with surface modification. The fabricated transparent films were composed of a hybrid ÀSi(CH 3) 3functionalized SiO 2 nanospheres exhibiting the desired micro/nanostructure, water repellency, and antireflection (AR) property. The wavelength selective AR property can be tuned by controlling the physical thickness of the films. Small-angle X-ray scattering (SAXS) studies revealed the existence of SiO 2 nanoparticles of average size ∼9.4 nm in the sols. TEM studies showed presence of interconnected SiO 2 NPs of ∼10 nm in size. The films were formed with uniformly packed SiO 2 aggregates as observed by FESEM of film surface. FTIR of the films confirmed presence of glasslike SiÀOÀSi bonding and methyl functionalization. The hydrophobicity of the surface was depended on the thickness of the deposited films. A critical film thickness (>115 nm) was necessary to obtain the air push effect for superhydrophobicity. Trimethylsilyl functionalization of SiO 2 and the surface roughness (rms ≈30 nm as observed by AFM) of the films were also contributed toward the high water contact angle (WCA). The coated glass surface showed WCA value of the droplet as high as 168 (3°with 6 μL of water. These superhydrophobic films were found to be stable up to about 230À240°C as confirmed by TG/DTA studies, and WCA measurements of the films with respect to the heat-treatment temperatures. These high water repellant films can be deposited on relatively large glass surfaces to remove water droplets immediately without any mechanical assistance.
The fabrication of black and electrically conducting films on glass substrate derived from covale... more The fabrication of black and electrically conducting films on glass substrate derived from covalently
functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO)
was first prepared following the Hummers method and then functionalized using an organically
modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion.
Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and
GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such
linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the
functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2)
atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as
black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded
organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to
1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely
correlated with the sheet resistance values.
Materials Advances, 2022
The present work describes the fabrication of functionalized mesoporous silica based antireflecti... more The present work describes the fabrication of functionalized mesoporous silica based antireflective-cum-hydrophobic coatings on textured solar cover glasses via a spray-coating technique exhibiting enhanced photo-current density.
Bulletin of Materials Science, 2008
ACS Applied Materials & Interfaces, 2011
The paper deals with the fabrication of solÀgel-derived superhydrophobic films on glass based on ... more The paper deals with the fabrication of solÀgel-derived superhydrophobic films on glass based on the macroscopic silica network with surface modification. The fabricated transparent films were composed of a hybrid ÀSi(CH 3) 3functionalized SiO 2 nanospheres exhibiting the desired micro/nanostructure, water repellency, and antireflection (AR) property. The wavelength selective AR property can be tuned by controlling the physical thickness of the films. Small-angle X-ray scattering (SAXS) studies revealed the existence of SiO 2 nanoparticles of average size ∼9.4 nm in the sols. TEM studies showed presence of interconnected SiO 2 NPs of ∼10 nm in size. The films were formed with uniformly packed SiO 2 aggregates as observed by FESEM of film surface. FTIR of the films confirmed presence of glasslike SiÀOÀSi bonding and methyl functionalization. The hydrophobicity of the surface was depended on the thickness of the deposited films. A critical film thickness (>115 nm) was necessary to obtain the air push effect for superhydrophobicity. Trimethylsilyl functionalization of SiO 2 and the surface roughness (rms ≈30 nm as observed by AFM) of the films were also contributed toward the high water contact angle (WCA). The coated glass surface showed WCA value of the droplet as high as 168 (3°with 6 μL of water. These superhydrophobic films were found to be stable up to about 230À240°C as confirmed by TG/DTA studies, and WCA measurements of the films with respect to the heat-treatment temperatures. These high water repellant films can be deposited on relatively large glass surfaces to remove water droplets immediately without any mechanical assistance.
The fabrication of black and electrically conducting films on glass substrate derived from covale... more The fabrication of black and electrically conducting films on glass substrate derived from covalently
functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO)
was first prepared following the Hummers method and then functionalized using an organically
modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion.
Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and
GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such
linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the
functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2)
atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as
black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded
organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to
1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely
correlated with the sheet resistance values.