arXiv subjects

S. A. Hussain

Publications and source records attributed to S. A. Hussain.

9 recordsLinked to original sources

arXiv2019

Unique supramolecular Assembly through Langmuir Blodgett technique

The Langmuir-Blodgett (LB) technique is a way of making supra-molecular assembly in ultrathin films with a controlled layered structure and crystal parameter, which have many envisioned technological applications for optical and molecular electronic devices as well as signal processing and transformation. Probably LB technique is the best method to manipulate materials at molecular level and provides a scope to realize the molecular electronics in reality. In this review article, this important film preparation has been discussed, highlighting its application potential.

physics.app-ph↗

arXiv2018

Wavelength tunable soliton rains in a nanotube-mode locked Tm-doped fiber laser

We report soliton rains in a tuneable Tm-doped fiber laser mode locked by carbon nanotubes. We also detect their second- and third-harmonic. We achieve a tuneability of over 56nm, from 1877 to 1933nm, by introducing a polarization-maintaining isolator and two in-line polarization controllers. This makes our system promising as a tuneable filter for ultrafast spectroscopy.

physics.optics↗

arXiv2012

An Improved XP Software Development Model

The concept of agile process models has attained great popularity in software (SW) development community in last few years. Agile models promote fast development. Fast development has certain drawbacks, such as weak documentation and performance for medium and large development projects. Fast development also promotes use of agile process models in small-scale projects. This paper modifies and evaluates Extreme Programming (XP) process model and proposes a novel process model based on these modifications.

cs.SE↗

arXiv2011

Adsorption of a Cationic Laser Dye onto Polymer/Surfactant Complex Film Fabricated by Layer-by-Layer Electrostatic Self-Assembly Technique

Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this short communication, we report the successful incorporation of cationic laser dye Rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/Surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly(allylamine hydrochloride) (PAH) was used as polycation and Sodium dodecyl sulphate(SDS) was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H and J-type aggregates in PAH/SDS/R6G complex LbL films as well as the kinetics of adsorption of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex films is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic Force Microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.

cond-mat.mtrl-sci↗

arXiv2011

Layer-by-Layer assembling and characterizations of dye-polyions onto solid substrate by Electrostatic adsorption process

Self assembled films of organic azobenzene dye chicago sky blue 6B (CSB) have been fabricated onto solid substarte by electrostatic alternate adsorption of polycation ploy(allyl amine hydrochloride) (PAH) and CSB. UV-Vis absorption spectroscopic studies reveal the successful incorporation of CSB molecules into LbL films and consequent formation of aggregates. This view is supported by FTIR spectroscopic studies. Scanning electron microscope picture confirms the formation of nano crystalline aggregates in the LbL films. About 15 minute is required to complete the electrostatic interaction between PAH and CSB molecules in one bi-layer LbL film.

cond-mat.mtrl-sci↗

arXiv2011

Investigations of RhB18 Langmuir monolayer by Fluorescence Imaging Microscopy

This communication reports the surface pressure vs. area per molecule isotherm and Fluorescence Imaging Microscopic studies of the formation of domain structure in the mixed Langmuir monolayer of RhB and Stearic acid (SA) at the air water interface. Strong repulsive interaction between the unlike components leads to the phase separation and formation of microcrystalline domains at the air water interface of the Langmuir monolayer. These domain can be directly visualized using fluorescence imaging microscope.

cond-mat.mtrl-sci↗

arXiv2008

Role of microenvironment in the mixed Langmuir-Blodgett films

This paper reports the pi-A isotherms and spectroscopic characteristics of mixed Langmuir and Langmuir-Blodgett (LB) films of non-amphiphilic carbazole (CA) molecules mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). pi-A isotherm studies of mixed monolayer and as well as also the collapse pressure study of isotherms definitely conclude that CA is incorporated into PMMA and SA matrices. However CA is stacked in the PMMA/SA chains and forms microcrystalline aggregates as is evidenced from the scanning electron micrograph picture. Nature of these aggregated species in the mixed LB films has been revealed by UV-Vis absorption and fluorescence spectroscopic studies. The presence of two different kinds of band systems in the fluorescence spectra of the mixed LB films have been observed. This may be due to the formation of low dimensional aggregates in the mixed LB films. Intensity distribution of different band system is highly sensitive to the microenvironment of two different matrices as well as also on the film thickness

cond-mat.mtrl-sci↗

arXiv2008

Photophysical characterizations of 2-(4-Biphenylyl)-5 phenyl-1,3,4- oxadiazole in restricted geometry

Langmuir and Langmuir-Blodgett (LB) films of nonamphiphilic 2-(4-Biphenylyl)-5 phenyl-1,3,4- oxadiazole (abbreviated as PBD) mixed with stearic acid (SA) as well as also with the inert polymer matrix poly(methyl methacrylate) (PMMA) have been studied. Surface pressure versus area per molecule (-A) isotherms studies suggest that PBD molecules very likely stand vertically on the air-water interface and this arrangement allows the PBD molecules to form stacks and remain sandwiched between SA/PMMA molecules. At lower surface pressure phase separation between PBD and matrix molecules occur resulting due to repulsive interaction. However at higher surface pressure PBD molecules form aggregates. The UV-Vis absorption and Steady state fluorescence spectroscopic studies of the mixed LB films of PBD reveal the nature of the aggregates. H-type aggregates predominates in the mixed LB films whereas I-type aggregates predominates in the PBD-PMMA spin coated films. The degree of deformation produced in the electronic levels are largely affected by the film thickness and the surface pressure of lifting.

cond-mat.mtrl-sci↗

arXiv2008

Spectroscopic characterizations of the mixed Langmuir-Blodgett (LB) films of 2,2'-biquinoline molecules: evidence of dimer formation

This communication reports the -A isotherms and spectroscopic characterizations of mixed Langmuir and Langmuir-Blodgett (LB) films of nonamphiphilic 2, -biquinoline (BQ) molecules, mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). The pi-A isotherms and molefraction versus area per molecule studies indicate complete immiscibility of sample (BQ) and matrix (PMMA or SA) molecules. This immiscibility may lead to the formation of microcrystalline aggregates of BQ molecules in the mixed LB films. The scanning electron micrograph gives the visual evidence of microcrystalline aggregates of BQ molecules in the mixed LB films. UV-Vis absorption, fluorescence and excitation spectroscopic studies reveal the nature of these microcrystalline aggregates. LB films lifted at higher surface pressure indicate the formation of dimer or higher order n-mers.

cond-mat.mtrl-sci↗