Srikanta Moharana; Anjali Kujur; Sudhir Minz; R. N. Mahaling; Banarji Behera
Abstract
Nickel ferrite [NiFe2O4 (NFO)] nanoparticles were synthesized using a simple precursor based chemical route and modified with tetraethoxysilane (TEOS) to form SiO2 layer adsorbed on the NFO particles (SiO2@NFO). Based on the nanoparticles, the SiO2@NFO-PMMA composite films were prepared embedded with ...
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Nickel ferrite [NiFe2O4 (NFO)] nanoparticles were synthesized using a simple precursor based chemical route and modified with tetraethoxysilane (TEOS) to form SiO2 layer adsorbed on the NFO particles (SiO2@NFO). Based on the nanoparticles, the SiO2@NFO-PMMA composite films were prepared embedded with SiO2@NFO nanoparticles in a poly (methylmethacrylate) (PMMA) matrix. The properties of the composites were characterized extensively using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, dielectric and electrical measurement. FTIR analysis showed that the SiO2 groups had been successfully introduced into the NFO nanoparticles. The SEM images of the SiO2 adsorbed NFO nanoparticles had better dispersion in the PMMA matrix than the unmodified one. The SiO2 modified NFO-PMMA composites had much higher dielectric constant and better suppressed dielectric loss than the other two phase composite systems. The maximum dielectric constant was up to ≈ 67 while the dielectric loss was controlled below 0.5. This study suggested that the SiO2 modified NFO-PMMA composite films with high dielectric constant and low loss might be promising candidates for application in microelectronic engineering.
Jia-Jia Shen; Jia He; Ya Ding
Abstract
Gold nanoparticles (GNPs) are of unique and interesting materials being firstly reported 100 years ago. They are one of the most widely studied nanomaterials potential for disease cure. To improve the colloidal stability, biocompatibility, and hemocompatibility of GNPs, chitosan (CS), a naturally produced ...
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Gold nanoparticles (GNPs) are of unique and interesting materials being firstly reported 100 years ago. They are one of the most widely studied nanomaterials potential for disease cure. To improve the colloidal stability, biocompatibility, and hemocompatibility of GNPs, chitosan (CS), a naturally produced polysaccharide with excellent biocompatibility and biodegradation, has been modified to generate water-soluble derivatives and used as the stabilizing agent of GNPs. In the presence of these derivatives, GNPs are stabilized, functionalized, and assembled via electronic static and covalent bond interactions. Based on these works, GNPs with different dimensional, morphology, and crystal lattice are obtained, which can be further apply to a variety of applications in sensing, imaging, therapy, and catalysis.
James Antony Prince; Sowrirajalu Bhuvana; Vanangamudi Anbharasi; K.V. Kamelia Boodhoo; Gurdev Singh
Abstract
Bio-fouling is a major issue in all membrane-based water treatment systems and there are several cleaning methods available to address this problem. Current membrane modification methods are focused on improving the hydrophilicity of membranes by blending hydrophilic additives or blending antibacterial ...
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Bio-fouling is a major issue in all membrane-based water treatment systems and there are several cleaning methods available to address this problem. Current membrane modification methods are focused on improving the hydrophilicity of membranes by blending hydrophilic additives or blending antibacterial compounds with the dope solution. In this study, we demonstrate a new method to impart bio-fouling resistance to a membrane surface by developing a water-insoluble unique copolymer additive, namely poly (acrylonitrile co maleic acid co di-amino maleio-nitrile) (PANCMACDAMN) with highly hydrophilic carboxylic and amine functional groups. Hydrophilic polyethylene glycol functionalized with silver (Ag) was grafted to the copolymer backbone to further improve the hydrophilicity. The final additive PEG-Ag attached PANCMACDAMN was used to modify polyethersulfone (PES) ultrafiltration (UF) membrane. Characterization tests indicate that the innovative surface chemistry increases the hydrophilicity of the membrane by reducing the water contact angle (CAw) by 78.1% and increases its permeability by 120% compared to the control membrane. More importantly, the innovative surface chemistry prevents protein attachment and exhibits inhibition to microbes even after 720 min of continuous protein solution filtration.
Krasimir Vasilev; Melanie Ramiasa-MacGregor
Abstract
This forward looking concise review describes recent advances in the field of nanoengineered plasma polymer films. These types of coatings are relevant in many fields of application and have gained substantial research and technological interest over the last decade. The review starts with an introduction ...
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This forward looking concise review describes recent advances in the field of nanoengineered plasma polymer films. These types of coatings are relevant in many fields of application and have gained substantial research and technological interest over the last decade. The review starts with an introduction of plasma polymerization as a technique for preparation for nanometer thin polymer-like coatings. This is followed by the examples of the use of nanoengineered plasma polymer coatings in applications relevant to biomedical devices. Applications in antibacterial coatings and drug delivery vehicles are discussed. Significant section of this paper is dedicated to cell guidance surfaces which have an extensive range of applications ranging from coatings for medical devices to research tools that can help unraveling complex biological questions and vehicles for the growing field of cell therapies. The vision of the authors about the future directions of the field have also been presented, including a section on novel oxazoline based coatings that carry great promise for advances in the biomaterial and biomedical fields.
Keisho Iimori; Ryo Endo; Kazuya Yamamoto; Jun-ichi Kadokawa
Abstract
Chitin is widely distributed in nature and an important renewable resource. However, it has been difficult to provide a wide variety of material applications from chitin, due to poor solubility and processability. In this study, we performed surface modification of self-assembled chitin nanofibers (CNFs) ...
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Chitin is widely distributed in nature and an important renewable resource. However, it has been difficult to provide a wide variety of material applications from chitin, due to poor solubility and processability. In this study, we performed surface modification of self-assembled chitin nanofibers (CNFs) by acetylation and their composite fabrication with a commodity plastic, low density polyethylene (LDPE). The self-assembled CNF dispersion with DMF was first prepared by regeneration from a chitin ion gel with an ionic liquid, 1-allyl-3-methylimidazolium bromide (AMIMBr), using methanol, followed by exchange of a dispersion medium according to the previously reported method by us. Surface acetylation of the product was then performed by reaction of acetic anhydride in the dispersion to obtain partially acetylated CNFs, which formed a film by isolation. The composites of the film with LDPE with the different weight ratios were fabricated by pressing at 170 o C at 0.1 MPa. The SEM measurements of the products observed the morphologies that LDPE interpenetrated from surfaces into cross-sections of the partially acetylated CNF films with increasing the LDPE ratios. The tensile testing of the composite films indicated reinforcing effect of LDPE present in the composites.
Sunita Gulia;Rita Kakkar
Abstract
Quantum dots (QDs), highly luminescent semiconductor nanocrystals, have found extensive applications in different fields, ranging from optoelectronic to bio-imaging. Numerous applications are emerging daily. Among these, ZnO QDs have higher biological significance because of their relative non-toxicity. ...
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Quantum dots (QDs), highly luminescent semiconductor nanocrystals, have found extensive applications in different fields, ranging from optoelectronic to bio-imaging. Numerous applications are emerging daily. Among these, ZnO QDs have higher biological significance because of their relative non-toxicity. The primary aim of this review is to overview the literature based on the biological applications of ZnO QDs, including gene therapy, drug delivery, optical imaging, allergen and antigen detection, cancer cell sensing, antibacterial agents and DNA detection. The luminescent properties of ZnO nanoparticles have attracted considerable attention for numerous applications like ultraviolet light emitting devices, flat panel displays, as low voltage phosphors and biosensing devices. The review throws light on the developments in fabrication techniques of nanometer-sized, water-dispersible, bio-compatible and stable ZnO QDs in aqueous medium for biological applications, including employing organic ligands, coating nanoparticles with inorganic shells, doping with a suitable element and capping nanoparticles surfaces with polymers. The low toxicity of ZnO and its high natural abundance make it a good alternative to cadmium based II-VI semiconductors, which cause toxicity via photoinduced reactive oxygen species (ROS) generation.
Nitu Bhatnagar; Sangeeta Jha; Shantanu Bhowmik
Abstract
PEEK (polyether etherketone) polymer, is increasingly used in many industrial applications as a replacement for metal components. In this investigation, attention is given to understand the chemical changes that have been introduced on the surface of PEEK, when surface of the PEEK is modified by low ...
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PEEK (polyether etherketone) polymer, is increasingly used in many industrial applications as a replacement for metal components. In this investigation, attention is given to understand the chemical changes that have been introduced on the surface of PEEK, when surface of the PEEK is modified by low pressure plasma under RF (radio frequency) glow discharge. The contact angle measurements show that the contact angle decreases after the plasma treatment which results in the increase in surface energy. This paper also discusses the common surface characterisation technique like Energy Dispersive Spectroscopy (EDS) analysis to determine the chemical changes that have been introduced on the surface.
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