Dr. Syed Arshad Hussain Wellcomes You

Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film
July 13, 2011, 1:48 pm
Filed under: Lab News, Laboratory news, Layer-by-Layer (LbL) films, Publications

Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film

Chinese Journal of Chemical Physics Volume 24 Number 3, Issue 3 (June 2011)

Pabitra Kumar Paul, Syed Arshad Hussain, Debajyoti Bhattacharjee  and Mrinal Pal


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 work, 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 layer-by-layber films as well as the adsorption kinetics 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.

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Recent paper from our lab @ Journal of Luminescence

J-aggregates of thiacyanine dye organized in LB films: Effect of irradiation of light

Syed Arshad Hussain E-mail The Corresponding Author, Dibyendu Dey, S.next term Chakraborty  and D. Bhattacharjee

Journal of Luminescence

Volume 131, Issue 8, August 2011, Pages 1655-1660


In the present communication we report the preparation and characterizations of Langmuir and Langmuir–Blodgett films of a thiacyanine dye N,N′-dioctadecyl thiacyanineperchlorate (NK) mixed with Octadecyl trimethyl ammonium bromide (OTAB). The relationship between the molar ratio of OTAB and NK and the orientation of molecules at the air–water interface was investigated using surface pressure-area per molecule (π–A) isotherm. UV–vis absorption and fluorescence spectroscopic investigations reveal that prominent J-aggregation of NK molecule was observed in the LB films lifted at higher surface pressure. This J-aggregation can be controlled by diluting the NK molecules with OTAB. It was observed that the J-aggregates of NK decayed to monomer and H-aggregates when the NK-LB film was exposed to a monochromatic light of wavelength 460 nm (λmax of J-aggregates).


► Langmuir and Langmuir–Blodgett films of a thiacyanine dye (NK). ► Formation of J-aggregation of NK molecule at higher surface pressures. ► Control of J-aggregates by mixing octadecyl trimethyl ammonium bromide. ► Irradiation of monochromatic light. ► J-aggregates of NK decayed to monomer and H-dimer.

Keywords: Langmuir–Blodgett; π-A isotherm; J-aggregate; Irradiation of light

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New paper @ Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
July 13, 2011, 1:03 pm
Filed under: Lab News, Laboratory news, Langmuir-Blodgett Films, Publications, Student

Adsorption kinetics of a fluorescent dye in a long chain fatty acid matrix
Syed Arshad Hussain, Soma Banik, S. Chakraborty and D. Bhattacharjee
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Volume 79, Issue 5, September 2011, Pages 1642-1647


This work reports the adsorption kinetics of a highly fluorescent laser dye rhodamine B (RhB) in a preformed stearic acid (SA) Langmuir monolayer. The reaction kinetics was studied by surface pressure–time (πt) curve at constant area and in situ fluorescence imaging microscopy (FIM). Increase in surface pressure (at constant area) with time as well as increase in surface coverage of monolayer film at air–water interface provide direct evidence for the interaction. ATR–FTIR spectra also supported the interaction and consequent complexation in the complex films. UV–vis absorption and Fluorescence spectra of the complex Langmuir–Blodgett (LB) films confirm the presence of RhB molecules in the complex films transferred onto solid substrates. The outcome of this work clearly shows successful incorporation of RhB molecules into SA matrix without changing the photophysical characteristics of the dye, thus making the dye material as LB compatible.



► Formation of stearic acid (SA) Langmuir monolayer at air–water interface. ► Injection of fluorescent laser dye rhodamine B (RhB) from the backside of the barrier. ► Monitoring the reaction kinetics by measuring surface pressure–time (πt) curve and in situ fluorescence imaging microscopy (FIM). ► Increase in surface pressure and surface coverage of monolayer film confirm adsorption of RhB onto SA monolayer. ► ATR–FTIR and UV–vis absorption spectra of RhB–SA LB film support the adsorption.

Keywords: Langmuir monolayer; Pressure–area isotherm; Reaction kinetics; FIM; Rhodamine

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Pre-PhD public seminar
September 2, 2010, 4:52 pm
Filed under: Laboratory news, PhD, Student

My student Mr. Dhananjay De has delivered his Pre-PhD public seminar on last 31st August, 2010.

Title of his PhD Theses is: “Spectroscopic Characterizations of  Organized Molecular Assemblies in Ultrathin Films Fabricated by  Layer- by- Layer (LbL) Self Assembled Technique”.

Mr. Dhananjay De is working as Asst. Professor of Physics in Tripura Institute of Technology, Tripura, India.

My recent publications

1. Langmuir-Blodgett monolayers of cationic dyes in the presence and absence of clay mineral layers: N,N’ -dioctadecyl thiacyanine, octadecyl rhodamine B and laponite.”
Syed Arshad Hussain, R. A. Schoonheydt
Langmuir (2010) [article in press]

2. Effect of nano-clay platelets on the J-aggregation of thiacyanine dye organized in Langmuir-Blodgett films
D. Bhattacharjee, Syed Arshad Hussain, S. Chakraborty, and R. A. Schoonheydt
Spectrochimica Acta Part A (2010) [article in press]

3. Fluorescence Resonance Energy Transfer between organic dyes adsorbed onto nano-clay and Langmuir–Blodgett (LB) films
Syed Arshad Hussain, S. Chakraborty, D. Bhattacharjee, R.A. Schoonheydt
Spectrochimica Acta Part A 75 (2010) 664–670

4. Reaction kinetics of organo-clay hybrid films: In-situ IRRAS, FIM and AFM studies
Syed Arshad Hussain, Md N. Islam, D. Bhattacharjee
Journal of Physics and Chemistry of Solids 71 (2010) 323–328

5. Photophysical studies of xanthene dye in alkanols and in inorganic ions
B Ganguly, R K Nath, S A Hussain and A K Panda
Indian J. Phys. 84 (6), 549-555 (2010)

6. Investigations of RhB18 langmuir monolayer by fluorescence imaging microscopy
S A Hussain, S Chakraborty and D Bhattacharjee
Indian J. Phys. 84 (6), 625-629 (2010)