Langmuir monolayer is a unique tool to characterize the interface which describes the properties of insoluble monolayer on the sub-phase. Langmuir monolayers have demonstrated the characteristics of many macromolecules as well as amphiphilic molecules at the air-water interface. We evaluated physiochemical characteristics of monoolein lipid Langmuir monolayers on different sub-phases. Interfacial behaviour of monoolein lipid was investigated using Wilhelmy plate pressure sensor technique to generate Langmuir isotherms to explore the effects of interactions with different sub-phases. Various salts alter the surface pressure of the Langmuir monolayer isotherms without the alteration of monolayer phase transitions. The finding of the present work can be effectively used for development of suitable biomedical formulations to offer sufficient strength of coating film with controlled topology and thickness using Langmuir-Blodgett film deposition technique. Addition of the suitable biocompatible ions in to the sub-phase is very crucial for their favourable interfacial interaction with the lipid molecules.
In recent years, synthesis and characterization of Ag-based materials has become an active area of research due to its application in medical area for having antimicrobial properties useful for prosthetic replacement. Pure HydroxyAPatite (HAP) and 1.5wt% Ag-doped HydroxyAPatite (AgHAP) were prepared by sol-gel process and characterized. Ca(NO3)2.4H2O was used as source of Ca precursor, P2O5 was used as a source of P precursor, and AgNO3 has been used as a source of Ag precursor. Pellets of HAP and AgHAP were made after precipitates were consolidated, dried in oven, grounded and sintered in a muffle furnace. Functional groups were determined using FTIR, and compound formations were investigated using XRD. Microstructural analysis was done using SEM and AFM. Wettability was studied using OCA in distilled water, and corrosion resistance and impedance analyses were carried out using ECA in Ringer solution. It was observed from AFM and XRD that grain size decreased from 7.05 ?m to 1.25 ?m. Improvement in corrosion resistance was observed in AgHAP. Wettability studies showed that AgHAP is more hydrophilic in comparison with pure HAP. A correlation between microstructures and properties of hydroxyapetites are discussed in this paper.
DNA ionogels prepared by adding 1-ethyl-3-methylimidazolium chloride on low energy gamma irradiated DNA solution samples reveal non-trivial self-assembly. Variations in secondary structure and low-frequency gel rigidity modulus G0 captured this unique hitherto unexplored features of these gels. Interestingly, at higher radiation dose (0 to 100 Gy) samples could partially lose their initial rigidity. Dynamic light scattering revels dose dependent relaxation dynamics corresponding to ergodicity breaking time. In particular, viscosity and rheology showed that the time of gelation tgel, temperature of gelation Tgel and strength of gelation G0 are gamma ray dose dependent. DNA Ionogel melting with temperature shows self-assembled characteristics of this biomaterial. Gelation kinetics of ionizing radiation treated DNA strands have been studied in literature.
Bent Core Mesogens are remarkably interesting achiral Liquid Crystals. These grab attention for their utility. The compound, taken for investigation, is a Schiff base addition product, composed of 2-(4β-aminophenyl)-5-(4?β-butyloxyphenyl)-1,3,4- thiadiazole and 4-n-hexadecyloxy salicylaldehyde. The property of this imine derivative is in accordance with liquid crystal and is a Bent Core Mesogen (BCM). The thin layers were prepared with the help of Langmuir-Blodgett apparatus. The morphology and photo-physical characteristics of thin films were examined in comparison to similar BCM derivative of 1,3,4-Oxadiazole. The expectation was the formation of monolayer of molecules on the substrate. Practically there were layer of clusters on the substrate. Both molecules form nano clusters. The typically different aggregates by the thiadiazole moiety in comparison to oxadiazole moiety are revealed. Cluster formation is also supported by the Atomic Force Microscopic (AFM) images.
Aluminium (Al) and its alloys are attractive for a variety of applications due to its advantages like light weight, ease of processing and high thermal/electrical conductivities. However, it suffers from shortcomings in terms of strength, wear resistance and corrosion resistance. Anodising is commonly used to improve the surface modification of Al alloys. This paper presents a review of anodising and related processes and updates the current status in this area. The chemical structure and the size of the oxide film are influenced by factors like temperature, type of electrolyte and current density/ applied voltage. Depending on the process parameters, the oxide film formed in this process can be thin, non-porous, thick, and porous. The hardness of the coating in anodizing is influenced by the parameters like coating thickness, voltage, current density, and temperature. Further, it is required to regulate the metal/oxide or film/solution interface at which the barrier film grows. In Plasma Electrolytic Oxidation (PEO), the modified version of anodising, and the selection of operating conditions influence coating morphology, structure and composition which in turn affect the wear resistance and corrosion properties. The properties of the coating in case of PEO process are influenced by the nature/structure of the base material, type/composition of electrolyte, temperature of the electrolyte during the process, oxidation time, and electrical parameter (current density and voltage). Understanding of the effect of these parameters on coating properties opens new vista for better application prospects.
