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Papers by Amitabha Bhattacharyya

Research paper thumbnail of Coinage Metal− N -Heterocyclic Carbene Complexes

Research paper thumbnail of Saponins from Albizia procera Extract: Surfactant Activity and Preliminary Analysis

Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2022

Research paper thumbnail of Studies on the phase transitions and molecular confromations in langmuir monolayers

Research paper thumbnail of Novel phase diagram of a mixed Langmuir monolayer of octylcyanobiphenyl and stearic acid

Europhysics Letters (EPL), 1998

We have studied the phase diagram of a mixed monolayer system of 4'-n-octyl-4-cyanobi... more We have studied the phase diagram of a mixed monolayer system of 4'-n-octyl-4-cyanobiphenyl (8CB) and stearic acid (SA) at the air-water interface by surface manometry and optical microscopic techniques. We found that in the mixture, a liquid condensed phase (also known as L2) was induced which does not occur in the monolayers of the individual components. The induction occurs over

Research paper thumbnail of Surface Rheology and Foam Stability of Mixed Surfactant−Polyelectrolyte Solutions†

We have studied the surface rheology of mixed solutions of anionic polyelectrolytes and cationic ... more We have studied the surface rheology of mixed solutions of anionic polyelectrolytes and cationic surfactants. Surface elasticity and viscosity exhibit a maximum at a surfactant concentration much smaller than that for solutions of the pure surfactant. Foaming and foam stability were found to depend on these coefficients, although a systematic relation is difficult to establish. Still more surprisingly, the behavior of foams and foam films is very different in these systems.

Research paper thumbnail of Coinage Metal—N-Heterocyclic Carbene Complexes

Research paper thumbnail of Gold (I) Complexes of N‐Heterocyclic Carbenes and Pyridines

… Journal of Inorganic …, 2009

Overall ten ionic [Au(NHC)(Py)][PF 6 ]-and [Au 2 (NHC) 2 (Py) 2 ]-[PF 6 ] 2-type complexes [NHC =... more Overall ten ionic [Au(NHC)(Py)][PF 6 ]-and [Au 2 (NHC) 2 (Py) 2 ]-[PF 6 ] 2-type complexes [NHC = N,NЈ-dialkylbenzimidazol-2ylidene, denoted as R 2-bimy with alkyl (R) being methyl (Me) or ethyl (Et), and Py = 4-substituted pyridine or 4,4Ј-bipyridine] have been prepared by incorporating various Pys into the Au I-NHC core with Au(NHC)Cl as starting material. Their crystal structures characterized by X-ray diffraction indicate a linearly coordinated Au I center and exhibit secondary forces such as Au•••Au, Au•••π, or π•••π interactions. The luminescent properties of these compounds were studied in the solid state. Density-functional theory calcula-[a

Research paper thumbnail of Natural surfactant system: precursor flow in one-shot two-dimensional foam drainage

The European Physical Journal E

Research paper thumbnail of Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants

We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the pre... more We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the presence of a cationic surfactant. The presence of an anionic surfactant is known to increase the microcapsule yield dramatically. We report that this is true for cationic surfactant also. The concentration of the surfactant is a crucial parameter in obtaining optimal yield and good quality microcapsules. We also propose a two-step process for the formation of the microcapsules.

Research paper thumbnail of Surface rheology and foam stability of mixed surfactant-polyelectrolyte solutions

Langmuir, 2000

... Bhattacharyya, ‡ Francisco Monroy, ‡ § Dominique Langevin,* ‡ and Jean-François Argillier ‖. ... more ... Bhattacharyya, ‡ Francisco Monroy, ‡ § Dominique Langevin,* ‡ and Jean-François Argillier ‖. Laboratoire de Physique des Solides, Université Paris Sud, Bâtiment 510, 91405 Orsay, France, and Institut Français du Pétrole, 4 Av Bois-Préau, 92852 Rueil-Malmaison, France. ...

Research paper thumbnail of Nature friendly cleaning: the detergency of hamburger seed

Journal of Physics: Conference Series

Detergents or surfactants are surface active agents, active at surfaces and interfaces. A surfact... more Detergents or surfactants are surface active agents, active at surfaces and interfaces. A surfactant molecule consists of two parts. One is water liking or hydrophilic and the other is water hating or hydrophobic. When added to water, they arrange themselves at the surface and reduce the surface tension. This surface tension reduction gives the wetting ability and hence the cleaning ability of any solution. On further increasing the concentration, the surface becomes saturated with molecules. Molecules added now go to the bulk of the liquid and form closed structures called micelles, where the hydrophilic parts surround the hydrophobic parts. This concentration is called critical micelle concentration. Surfactants are widely used in homes and industry for cleaning and other purposes. Commercially prepared chemical detergents are toxic and harmful to the environment, while biochemical detergents, obtained from plants are less toxic. We report our work on the surface activity and cleaning ability of the seeds of Mucuna gigantea, commonly known as hamburger seed. The extract of the insides of the seeds show good surface tension reduction and foaming. We have also studied the dirt dispersion and other relevant properties of the extract. Our studies show that the seeds can probably supply a good natural detergent, biodegradable and environment friendly.

Research paper thumbnail of An Alternative Approach for Determining Critical Micelle Concentration: Dispersion of Ink in Foam

Journal of Surfactants and Detergents

Research paper thumbnail of Unusual Features in the Surface Pressure – Area Isotherms in the Langmuir Monolayer of a Siloxane Polymer

Molecular Crystals and Liquid Crystals

ABSTRACT

Research paper thumbnail of Quest for an eco-friendly alternative surfactant: Surface and foam characteristics of natural surfactants

Journal of Cleaner Production, 2017

Research paper thumbnail of High resolution x-ray reflectivity studies of ultra-thin films of liquid crystals

Research paper thumbnail of Shampoos Then and Now : Synthetic versus Natural *#

Journal of Surface Science and Technology

Hair care has been important to mankind from times immemorial. The market today is replete with s... more Hair care has been important to mankind from times immemorial. The market today is replete with synthetic hair care products, pushing natural materials to the background. These natural materials, being produced from plants, are biodegradable and non-toxic. In a bid to investigate natural products, we studied the surface tension, foaming and relevant parameters of natural surfactants extracted from Shikakai (Acacia concinna) and Seto Siris (Albizia procera), traditionally used in hair care. In order to get a better understanding, Johnson's Baby Shampoo has also been studied. Shikakai showed very prominent surface tension reduction and high foaming, showing that it can be a potential candidate for good hair care. These effects are not so prominent for Seto Siris. However, as it is widely available in the hills, large quantities can be used. Qualitative measurement of their cleaning properties and subsequent comparison with commercial shampoo show that both plants have a large potential in providing nontoxic natural hair care products.

Research paper thumbnail of Meghnad Saha’s Paradoxical Story: Railways and the 1922 North Bengal Floods

The destruction caused by flood is well known. The effect of dams and barrages on floods is well ... more The destruction caused by flood is well known. The effect of dams and barrages on floods is well documented. However, the effects of other structures, especially railway structures in causing floods are not well understood. In general, railways are portrayed as bearing the brunt of floods, or are praised for helping in relief activities. This article would like to highlight the role of railway embankments in trapping rain water and aggravating floods. Starting from the groundbreaking work of Meghnad Saha in 1922-23, the article follows the evolution of understanding of the role of embankments in causing and aggravating floods, and the steps required to prevent or minimize the harm done. The present scenario in the context of rapid urbanization and mushrooming of development is also being explored.

Research paper thumbnail of Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants

Journal of Surface Science and Technology

We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the pre... more We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the presence of a cationic surfactant. The presence of an anionic surfactant is known to increase the microcapsule yield dramatically. We report that this is true for cationic surfactant also. The concentration of the surfactant is a crucial parameter in obtaining optimal yield and good quality microcapsules. We also propose a two-step process for the formation of the microcapsules.

Research paper thumbnail of Margin to Metropolis: Lepchas of India and Igbos of Nigeria

Research paper thumbnail of King Topocles and the Mythical Origin of Modern Physics

Journal of Advanced Studies in Topology

The basic pillars of physics, namely classical mechanics, quantum mechanics and theory of relativ... more The basic pillars of physics, namely classical mechanics, quantum mechanics and theory of relativity are taught in colleges all over the country. It is the experience of the author and many others that the concepts are difficult for many students to follow, not only because they are involved, but also due to the absence of a non-mathematical treatment. In this article, I have attempted to explain all the concepts in the form of a fantastic story, set in an ancient Greece of my imagination.

Research paper thumbnail of Coinage Metal− N -Heterocyclic Carbene Complexes

Research paper thumbnail of Saponins from Albizia procera Extract: Surfactant Activity and Preliminary Analysis

Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2022

Research paper thumbnail of Studies on the phase transitions and molecular confromations in langmuir monolayers

Research paper thumbnail of Novel phase diagram of a mixed Langmuir monolayer of octylcyanobiphenyl and stearic acid

Europhysics Letters (EPL), 1998

We have studied the phase diagram of a mixed monolayer system of 4'-n-octyl-4-cyanobi... more We have studied the phase diagram of a mixed monolayer system of 4'-n-octyl-4-cyanobiphenyl (8CB) and stearic acid (SA) at the air-water interface by surface manometry and optical microscopic techniques. We found that in the mixture, a liquid condensed phase (also known as L2) was induced which does not occur in the monolayers of the individual components. The induction occurs over

Research paper thumbnail of Surface Rheology and Foam Stability of Mixed Surfactant−Polyelectrolyte Solutions†

We have studied the surface rheology of mixed solutions of anionic polyelectrolytes and cationic ... more We have studied the surface rheology of mixed solutions of anionic polyelectrolytes and cationic surfactants. Surface elasticity and viscosity exhibit a maximum at a surfactant concentration much smaller than that for solutions of the pure surfactant. Foaming and foam stability were found to depend on these coefficients, although a systematic relation is difficult to establish. Still more surprisingly, the behavior of foams and foam films is very different in these systems.

Research paper thumbnail of Coinage Metal—N-Heterocyclic Carbene Complexes

Research paper thumbnail of Gold (I) Complexes of N‐Heterocyclic Carbenes and Pyridines

… Journal of Inorganic …, 2009

Overall ten ionic [Au(NHC)(Py)][PF 6 ]-and [Au 2 (NHC) 2 (Py) 2 ]-[PF 6 ] 2-type complexes [NHC =... more Overall ten ionic [Au(NHC)(Py)][PF 6 ]-and [Au 2 (NHC) 2 (Py) 2 ]-[PF 6 ] 2-type complexes [NHC = N,NЈ-dialkylbenzimidazol-2ylidene, denoted as R 2-bimy with alkyl (R) being methyl (Me) or ethyl (Et), and Py = 4-substituted pyridine or 4,4Ј-bipyridine] have been prepared by incorporating various Pys into the Au I-NHC core with Au(NHC)Cl as starting material. Their crystal structures characterized by X-ray diffraction indicate a linearly coordinated Au I center and exhibit secondary forces such as Au•••Au, Au•••π, or π•••π interactions. The luminescent properties of these compounds were studied in the solid state. Density-functional theory calcula-[a

Research paper thumbnail of Natural surfactant system: precursor flow in one-shot two-dimensional foam drainage

The European Physical Journal E

Research paper thumbnail of Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants

We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the pre... more We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the presence of a cationic surfactant. The presence of an anionic surfactant is known to increase the microcapsule yield dramatically. We report that this is true for cationic surfactant also. The concentration of the surfactant is a crucial parameter in obtaining optimal yield and good quality microcapsules. We also propose a two-step process for the formation of the microcapsules.

Research paper thumbnail of Surface rheology and foam stability of mixed surfactant-polyelectrolyte solutions

Langmuir, 2000

... Bhattacharyya, ‡ Francisco Monroy, ‡ § Dominique Langevin,* ‡ and Jean-François Argillier ‖. ... more ... Bhattacharyya, ‡ Francisco Monroy, ‡ § Dominique Langevin,* ‡ and Jean-François Argillier ‖. Laboratoire de Physique des Solides, Université Paris Sud, Bâtiment 510, 91405 Orsay, France, and Institut Français du Pétrole, 4 Av Bois-Préau, 92852 Rueil-Malmaison, France. ...

Research paper thumbnail of Nature friendly cleaning: the detergency of hamburger seed

Journal of Physics: Conference Series

Detergents or surfactants are surface active agents, active at surfaces and interfaces. A surfact... more Detergents or surfactants are surface active agents, active at surfaces and interfaces. A surfactant molecule consists of two parts. One is water liking or hydrophilic and the other is water hating or hydrophobic. When added to water, they arrange themselves at the surface and reduce the surface tension. This surface tension reduction gives the wetting ability and hence the cleaning ability of any solution. On further increasing the concentration, the surface becomes saturated with molecules. Molecules added now go to the bulk of the liquid and form closed structures called micelles, where the hydrophilic parts surround the hydrophobic parts. This concentration is called critical micelle concentration. Surfactants are widely used in homes and industry for cleaning and other purposes. Commercially prepared chemical detergents are toxic and harmful to the environment, while biochemical detergents, obtained from plants are less toxic. We report our work on the surface activity and cleaning ability of the seeds of Mucuna gigantea, commonly known as hamburger seed. The extract of the insides of the seeds show good surface tension reduction and foaming. We have also studied the dirt dispersion and other relevant properties of the extract. Our studies show that the seeds can probably supply a good natural detergent, biodegradable and environment friendly.

Research paper thumbnail of An Alternative Approach for Determining Critical Micelle Concentration: Dispersion of Ink in Foam

Journal of Surfactants and Detergents

Research paper thumbnail of Unusual Features in the Surface Pressure – Area Isotherms in the Langmuir Monolayer of a Siloxane Polymer

Molecular Crystals and Liquid Crystals

ABSTRACT

Research paper thumbnail of Quest for an eco-friendly alternative surfactant: Surface and foam characteristics of natural surfactants

Journal of Cleaner Production, 2017

Research paper thumbnail of High resolution x-ray reflectivity studies of ultra-thin films of liquid crystals

Research paper thumbnail of Shampoos Then and Now : Synthetic versus Natural *#

Journal of Surface Science and Technology

Hair care has been important to mankind from times immemorial. The market today is replete with s... more Hair care has been important to mankind from times immemorial. The market today is replete with synthetic hair care products, pushing natural materials to the background. These natural materials, being produced from plants, are biodegradable and non-toxic. In a bid to investigate natural products, we studied the surface tension, foaming and relevant parameters of natural surfactants extracted from Shikakai (Acacia concinna) and Seto Siris (Albizia procera), traditionally used in hair care. In order to get a better understanding, Johnson's Baby Shampoo has also been studied. Shikakai showed very prominent surface tension reduction and high foaming, showing that it can be a potential candidate for good hair care. These effects are not so prominent for Seto Siris. However, as it is widely available in the hills, large quantities can be used. Qualitative measurement of their cleaning properties and subsequent comparison with commercial shampoo show that both plants have a large potential in providing nontoxic natural hair care products.

Research paper thumbnail of Meghnad Saha’s Paradoxical Story: Railways and the 1922 North Bengal Floods

The destruction caused by flood is well known. The effect of dams and barrages on floods is well ... more The destruction caused by flood is well known. The effect of dams and barrages on floods is well documented. However, the effects of other structures, especially railway structures in causing floods are not well understood. In general, railways are portrayed as bearing the brunt of floods, or are praised for helping in relief activities. This article would like to highlight the role of railway embankments in trapping rain water and aggravating floods. Starting from the groundbreaking work of Meghnad Saha in 1922-23, the article follows the evolution of understanding of the role of embankments in causing and aggravating floods, and the steps required to prevent or minimize the harm done. The present scenario in the context of rapid urbanization and mushrooming of development is also being explored.

Research paper thumbnail of Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants

Journal of Surface Science and Technology

We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the pre... more We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the presence of a cationic surfactant. The presence of an anionic surfactant is known to increase the microcapsule yield dramatically. We report that this is true for cationic surfactant also. The concentration of the surfactant is a crucial parameter in obtaining optimal yield and good quality microcapsules. We also propose a two-step process for the formation of the microcapsules.

Research paper thumbnail of Margin to Metropolis: Lepchas of India and Igbos of Nigeria

Research paper thumbnail of King Topocles and the Mythical Origin of Modern Physics

Journal of Advanced Studies in Topology

The basic pillars of physics, namely classical mechanics, quantum mechanics and theory of relativ... more The basic pillars of physics, namely classical mechanics, quantum mechanics and theory of relativity are taught in colleges all over the country. It is the experience of the author and many others that the concepts are difficult for many students to follow, not only because they are involved, but also due to the absence of a non-mathematical treatment. In this article, I have attempted to explain all the concepts in the form of a fantastic story, set in an ancient Greece of my imagination.