. SUPER HYDROPHOBICITY Soumya Ranjan Sahoo (711CH1025) NIT, Rourkela Abstract: Superhydrophobicity as a sensation has turned into an increasing focus of research and technological movement, where its key viewpoints span surface chemistry, chemical physics, and cellular biology. Hydrophobic particles have a tendency to be non-polar and, accordingly, incline toward other neutral molecule and non-polar solvents. Hydrophobic atoms in water frequently bunch together, shaping micelles. Water on hydrophobic surfaces will display a high contact point.
Strong hydrogen bonding interactions between amide groups back up some typical weakness of aliphatic polyester. The properties of polymer like hydrophilic or hydrophobic ratio and biodegradability easily adjusted. Synthesis of Polyesteramides: Polyesteramides can be prepared from different monomers and lead to random, blocky and ordered microstructures. The monomers of the polyesteramides are esters and amide bonds linked to each other, which have good vulnerability for
Each exhibits unique chemical reactivity. These molecules will react with atmospheric moisture or water adsorbed on a surface to form silanols, while liberation of the corresponding by-product will occur (e.g., HCl, NH3, alcohol or carboxylic acid). These silanols can then react with other silanols to form a stable siloxane bond (-Si-O-Si-). In the presence of hydroxyl groups at the surface of glass, minerals or metals (e.g., aluminum, steel), silanols will form a stable M–O-Si bond (M = Si, Al, Fe, etc.). This is the key chemistry that allows silanes to function as valuable surface-treating or “coupling”
Second the protein has a complex molecular structure and one should expect protein- protein interactions to be highly directional. Protein self-association can be triggered by chemical transformations; it is also sensitive to physical parameters such as temperature and pressure. Moreover, it is strongly affected by changes in the properties of the medium, such as, pH, the electrolyte concentration, and the presence of co solvents or additives (Stenstan et al.
It occurs when there is an absence of seed crystal or nucleus (nucleation points) for the formation of a crystal lattice structure by water molecules. It is found out that hot water would supercool lesser than cold water (i.e. hot water freezes at a higher temperature than cold water). Auerbach (1995) found out that that the most probable freezing temperature, Tf of hot water at 90oC was at 0oC - -2oC, with a probability of 0.41, Whereas Tf of cold water at 18oC was at -4oC to -6oC, with a probability of 0.56 However, the reason behind supercooling on the Mpemba Effect was not determined. In fact, theoretically, hot water should supercool less than cold water, due to the fact that hot water contains lesser amounts of dissolved gases than cold water as these gases were driven off in the process of heating the water.
The study of time, enzyme loading, temperature, molar ratio and speed of agitation were studied in a solvent free system at a time. The lipase catalyzed synthesis of flavor involves interactions among several variables, therefore traditional method is inefficient for optimization of reaction. Response surface methodology (RSM) is a statistical model approach for empirical modelling which evaluates the effect of individual and interaction effects of the process parameters on the corresponding response value. In preliminary single factor method analysis the molar ratio, enzyme loading and temperature were showing significant effects on esterification synthesis, thus these variables were selected for study response surface methodology. Design Expert 7.0 software was used for the designing the experiments and for analysis of the data.
Engineers came up with idea of using different types of fluids that can change its property according to the external forces. For example MR (Magneto-Rheological) fluids and ER (Electro-Rheological) fluids. MR fluids are materials that expose a change in rheological properties such as elasticity, viscosity or plasticity with the application of a magnetic field. On the other hand, ER fluids alters its rheological property when an electric field is applied to the fluid. MR fluids require small voltages and current, while ER fluids require very large voltage and very small currents.
The appropriate combination of dissociation of the components due to the addition of the second component, the existence of weak forces between unlike molecules and differences in sizes and shapes of the components affects the sign and magnitude of the excess isentropic compressibilities . The values in liquid mixtures depends on the molecular structure of component liquids, and influenced by other factors like dipole-dipole interactions, hydrogen bonding, and charge transfer interactions and or complex formation. An examination of data in Table 4 cause that the factors causes for negative excess isentropic compressibilities were dominant in the binary mixtures of N-methylformamide with ketones at (303.15 to 318.15) K. The observed negative values indicate that dipole-dipole interaction between unlike molecules is stronger than N-methylformamide- N-methylformamide or ketone-ketone interactions in all the systems under study . The algebraic values fall in the order cyclopentanone > cyclohexanone >
Since ferrocene is highly reactive (due to its two cyclopentadienyl rings), AlCl3 can be replaced with a more benign catalyst, phosphoric acid. This reaction will also use acetic anhydride in place of an alkyl halide. Figure 2 shows the mechanism for this
There is a diverse range of chemical groups and reactions that give rise to the exquisite photochromic effect. For instance, cis-trans isomerizations or geometric isomerism, where the functional group of a molecule is rotated into a different position or orientation, retaining the same molecular formula. Then there are pericyclic reactions, following UV exposure, the molecule switches to form B by the rearrangement of bonds. The Spiropyrans, the most prevalent class of photochromes, are a good example. When exposed to high energy UV, the sp³-hybridized carbon-oxygen bond in a Spiropyran breaks and opens the ring such that the carbon becomes sp² hybridized.