Physicochemical Studies On Carboxymethylcellulose Sodium Salt, Dyes And Surfactants

Size: px

Start display at page:

Download "Physicochemical Studies On Carboxymethylcellulose Sodium Salt, Dyes And Surfactants"

Delphia Martin
5 years ago
Views:

1 International Journal Of Scientific Research And Education Volume 2 Issue 9 Pages September-2014 ISSN (e): Website: Physicochemical Studies On Carboxymethylcellulose Sodium Salt, Dyes And Surfactants Authors Banti Ganguly 1, R.K. Nath 2 1 Department of Chemistry, Dasaratha Deb Memorial College, Khowai, Tripura,India 2 Department of Chemistry, Tripura University, Suryamaninagar, Tripura, India Corresponding Author Banti Ganguly Department of Chemistry, DDM College, Khowai, Tripura, India Pin Ph: ,Fax: mamon.0123@gmail.com ABSTRACT: The binding behavior of carboxymethylcelloluse (CMC) sodium salt with oppositely charged dyes have been studied by way of absorbance and emission spectroscopic measurements. The anionic polyelectrolyte exhibited chromotropic character and induced strong metachromasy in the cationic dye, pinacyanol chloride (PIN) through the formation of a 1:1 stoichiometric complex. Evaluation of thermodynamic parameters, viz., changes in free energy ( G O ), enthalpy ( H O ), and entropy ( S O ), for the formation of dyepolymer complex and studies on the effect of different cosolvents were also evaluated to shed light on the binding nature as well as the extent of stability of thedye-polymer complex. Fluorescence of the cationic dye Acridine orange (AO) was quenched with the progressive addition of carboxymethylcelloluse (CMC) sodium salt, which was found to be of Stern-Volmer type. Addition of different cosolvents resulted reversal of metachromasy. The interaction of cationic surfactants with carboxymethylcelloluse (CMC) sodium salt has been studied by turbidemetric technique. Keywords: Carboxymethylcelloluse, pinacyanol chloride, metachromasy, acridine orange, surfactant INTRODUCTION Carboxymethylcelloluse (CMC) sodium salt is one of the most important semi-synthetic derivatives of cellulose [1]. CMC is water soluble linear polymer produced by partial substitution of the 2,3 and 6 hydroxy methyl groups of cellulose by hydrophobic carboxy methyl group. CMC chains are linear β (1 4) glucopyranose polymer of cellulose (Scheme-1) whose polyelectrolytic character is due to the presence of Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1860

2 weakly acidic group. At P H > 4 it behaves as poly anion [2]. CMC is generally found in a water soluble form as sodium salt. It has currently been used in the paint, food and cosmetic industries as a thickener. Pinacyanol chloride (1,1'-diethyl-2,2'-carbocyanine) (PIN) is a cationic dye that belongs to the class of conjugated cyanine dyes. The amphipathic nature of these dyes confers solubility in a wide range of solvents, including water and chloroform. It can form aggregates. A strong dispersion force associated with the high polarizability of the chromophoric chain favors the aggregation of cyanine dyes in aqueous solution. The high dielectric constant of water facilitates the aggregation process by reducing theelectrostatic repulsion between similarly charged dyemolecules [3]. Cyanine dyes are intensively colored, polymethine dyes and have been frequently used as optical probes in the study of membranes, surfactants, micelles, proteins, amyloid fibrils, and dendrimer-based host systems [4-7]. As a redox indicator, it is used to monitor peroxide activation [8]. Studies on the interaction of biomacromolecules with dyes are considered to be significant as such studies are beneficial in understanding the physiology, biochemistry and physical chemistry of macromolecules. Such studies are usually done by spectroscopic methods very dilute solutions of dyes are used. Metachromasy is a well-known phenomenon in case of dye-polymer interaction and is generally applied to the aggregation of cationic dye on anionic polymers and colloids [9].The phenomena have also been observed in few cases of cationic polyelectrolyte and anionic dye systems. Reports dealing with studies on dye-polymer inter-action inducing metachromasy in different cationic dyes by different synthetic polyanions, DNA, and naturally occurring plant polyelectrolytes are also available. A clear idea about the mechanism of polyion induced metachromasy and the correlations between the dye structures and metachromatic behaviors could be obtained through such studies, for example, interaction of heparins with azure dyes [10]. The concept of reversal of metachromasy can be used to determine the stability of the metachromatic complex. Reversal of metachromasy may be attained with the addition of urea, alcohol, electrolytes, and also with increasing the temperature of the dye-polymer aggregate [11]. Evaluation of different thermodynamic parameters like changes in free energy ( G O ), enthalpy ( H O ) and can also predict about the optimum conditions for the interaction between the oppositely charged dye and macromolecules. Fluorescence spectroscopic measurements are assumed to provide useful information about dye polymer complex formation. Number of binding sites on the polymer molecule can be evaluated from fluorescence quenching technique [12].Fluorescence quenching is a process of deactivation of the excited state which results in a decrease in fluorescence intensity. Acridine orange (AO) could be used as a photophysical probe under the influence of different polymer matrices [13-14].Interaction of polymers and surfactants in aqueous medium are common in many industrial processes. Such interaction provides special effects such as enhancing the surface activity, stabilising foams and emulsions [15]. Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1861

3 The present investigation deals with the studies on interaction between anionic polyelectrolyte CMC and cationic dye pinacyanol chloride and acridine orange in aqueous medium. Spectrophoto-fluorimetric techniques were used for detailed study of dye-polymer interaction. Thermodynamic parameters of interaction and effects of different co-solvents were evaluated. The behaviour of the CMC towards surfactants is studied. Further we have compared the binding capability of the surfactants to the CMC. EXPERIMENTAL DETAILS Carboxymethylcellolose sodium salt (CMC), Pinacyanol Chloride (PIN) and Acridine Orange (AO) were purchased from Sigma Aldrich Co. (USA) and were used as such. Solvents were supplied from E.Merck, Germany. Double distilled water with a specific resistively of 18mΩ cm 1 wasused during the experiment.absorbance measurements were done at wavelength ranging from nmwith a spectrophotometer (Lambda 25, Perkin Elmer, USA).Fluorescence measurements were done in spectrofluorometer (RF-5000,Shimadzu, Japan). Concentrations of the aqueous dyes, andpolymer were in the range of 10 5 to 10 3 mol dm 3. Acridine orange was excited at 480 nm. The general experimental details for the measurement of absorbance, fluorescence, determination of stoichiometry, spectrophotometric titration and reversal of metachromasy are available in literature [16, 12].Turbidity experiments were performed by recording by the % transmission (%T) at 420 nm on a Milton Roy Spectronic -21D spectrophotometer. Turbidity was expressed as (100-T%). RESULTS AND DISCUSSION Absorption spectra of Pinacyanol chloride with CMC Polyelectrolytic properties of the CMC polymer were investigated with respect to binding of cationic dye pinacyanol chloride (PIN). Inaqueoussolution, the absorption spectra of the PIN monomer exhibits thestrongest band at 600 nm (monomeric band), whereas another bandis observed at 545 nm. This band corresponds to the dimeric state ofthe dye molecule. Inductions of metachromasy[17-18] in the dye molecule by the polymers were studied by spectral measurement and it has been seen from Fig. 1 that a metachromatic blue shift about 100 nm occurs in the visible range during the dye-polymer interaction.upon addition of CMC, the dye polymer mixture exhibited blue-shifted metachromaticband (H-band) with a peak near 500 nm. At lower P/D, multiple banded spectra were noted, which represent random coil structure of the polymer [16, 19]. Dye molecules could form a charge transfer complex with the CMC, hence due to theformation of a charge transfer complex a blue shift in the original bandof the dye molecule occurred. Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1862

Scheme 1: Structure of CMC Fig 1: Absorption spectra of 10-5 mol.dm -3 PIN in presence of varying amount of CMC at 303 K.CMC/PCYN (P/D) ratio 0, 0.

8,1, 2, 5,10,15,20,30,50 Determination of Stoichiometry of dye-polymer mixture Stoichiometry of the dye-polymer compound was determined according

suggesting stacking conformation of the polymer [21] as shown in Fig.2.Increasing amount of CMC solution (0.1 2.

The metachromatic solutions were isolated with petroleum ether and the uncomplexed dye concentration was determined spectrophotometrically.

4 Scheme 1: Structure of CMC Fig 1: Absorption spectra of 10-5 mol.dm -3 PIN in presence of varying amount of CMC at 303 K.CMC/PCYN (P/D) ratio 0, 0.2,0.4, 0.8,1, 2, 5,10,15,20,30,50 Determination of Stoichiometry of dye-polymer mixture Stoichiometry of the dye-polymer compound was determined according to MacIntosh method [20] at 600nm by spectrophotometricaly method and indicated stoichiometry of the dye pinacyanol chloride and CMC as ~1:1 suggesting stacking conformation of the polymer [21] as shown in Fig.2.Increasing amount of CMC solution ( ml, 10 μmol dm 3 )was added to fixed amount of 10 μmol dm 3 PIN. The metachromatic solutions were isolated with petroleum ether and the uncomplexed dye concentration was determined spectrophotometrically. Concentration of complexed dye was plotted against the concentration of added polymer. From the point of intersection of two linear plots, the stoichiometry of dye polymer complex was evaluated. 1:1 stoichiometry of the metachromatic compound suggestedthat every potential anionic site of repeating unit of polymer was associated with the dye. Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1863

Addition of alcohols increased the intensity of absorption of PIN.

5 Fig 2: Determination of stoichiometry of CMC PIN complex by MacIntosh method at 298 K. Reversal of metachromasy using alcohols The effect of non-aqueous solvents on the reversal of metachromasy is shown in Fig. 3 for methanol as representative. Addition of alcohols increased the intensity of absorption of PIN. In presence of40% methanol and 30% ethanol at P/D=5, the metachromatic band was completely disappeared and spectra became identical to that of the pure dye solution in similar alcoholic medium. These alcohols can strongly influence the aggregation behavior of amphipathic dye molecule like PIN [22]. The overall polarity of the medium decreased with the addition of alcohol, thus electrostatic interaction between dye and polymer became less favourable. Moreover alcohol enhanced the process of monomerization of the dye, which resulted in increase in the intensity of the monomeric band of PIN. The polarity of the medium decreased with the increase in alkanol chain length thus the efficiency of alcohol in disrupting the metachromatic band increased with the increase in alcohol chain length. Fig 3: Effect of methanol on CMC PIN complex at 303 K. [PIN]=10 μmol dm 3 Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1864

Determination of thermodynamic parameters Thermodynamic parameters such as interaction constant (K C ),changes in standard free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy(δs 0 ) of the dye polymer

6 Determination of thermodynamic parameters Thermodynamic parameters such as interaction constant (K C ),changes in standard free energy (ΔG 0 ), enthalpy (ΔH 0 ) and entropy(δs 0 ) of the dye polymer complex at different temperatures were obtained using the Rose and Drago equation [23] Plots of (C D C S )/(A A O ) vs. C S at different temperatures is shown in Fig. 4. Results are summarized intable 1. K C values were found to decrease with rise in temperature, revealing the binding process to be exothermic in nature [24,22].The values of free energy change were determined at all temperatures with the help of the equation G O =-RT lnk C. The value of enthalpy change, H O was obtained from the plot of ln K versus 1/T and S O entropy change was obtained from the plot of G O versus T according to the equation G O = H O T S O. Higher values of free energy change indicated the dye polymer aggregation to be controlled both by electrostatic and hydrophobic interactions [22,24,25]. Values of the entropy and enthalpy changes were found to be within the range of reversible biological processes. Negative value of entropy change also indicated formation of ordered structures during the interaction of PIN with CMC [16, 19]. Fig 4: Plot of C D C S /(A A O )versus C S to determine the PIN CMC interaction constant at differenttemperatures. [PIN]=10 μmol dm 3. Temperature (K):, 303;, 308; Δ, 313 and, 318. Table 1: Thermodynamic parameters for the interaction of PIN with CMC Temp./ K 10-4KC (dm3 mol-1) GO (kcal mol- HO (kcal mol- 1) 1) SO (Cal mol- 1deg-1) Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1865

Fluorescence spectra of Acridine orange with CMC Fluorescence studies on the interaction of CMC with AO were carried out by recording the emission spectra of the dye and the dye-polymer mixture at

5 nm (λ em ), as shown in Fig. 5.It was found that progressive addition of CMC quenched the fluorescence of acridine orange in aqueous medium.

7 Fluorescence spectra of Acridine orange with CMC Fluorescence studies on the interaction of CMC with AO were carried out by recording the emission spectra of the dye and the dye-polymer mixture at different P/D. Aqueous solution of AO was excited at 480 nm (λ ex ) and fluorescence intensity was recorded at 525 nm (λ em ), as shown in Fig. 5.It was found that progressive addition of CMC quenched the fluorescence of acridine orange in aqueous medium. The ratio of fluorescence intensity of pure dye (F O ) and dye CMC mixture (F) was plotted against the concentration of CMC, where CMC acted as quencher (Q).The plot is shown as inset in Fig. 5. Fluorescence quenching was found to be of Stern Volmer type. Binding constant (K SV ) of the dye polymer complex was determined using Stern Volmer equation [26]: F 0 Fo K SV [Q] (2) K SV was found to be 0.82x10 4 dm 3 mol -1.Efficiency of CMC quencher to fluorescence dye AO is an established fact [12, 16, 19, 24]. CMC being anionic in nature could donate their electrons to the cationic dye through the formation of charge transfer complex. This would eventually reduce the transition probability of electrons of AO bonding molecular orbital to the antibonding/nonbonding molecular orbital. Thus the fluorescence of AO got quenched upon the addition ofcmc to the aqueous AO solution. Linear plot with unit intercept indicated Stern Volmer type of quenching. Fig 5: Emission spectra of 10 5 mol dm 3 AO at 303 K in presence of varying amounts of CMC.(10 μmoldm 3 )=1. 0; 2.1; 3.2; 4.5; 5.10; 6.20; 7.30 and λ ex, 480 nm. Inset: Stern Volmer plot for determining K sv for CMC AO complex. Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1866

Interaction of CMC with cationic surfactants Turbidity was observed when oppositely charged surfactants were added to the aqueous CMC solution.

8 Interaction of CMC with cationic surfactants Turbidity was observed when oppositely charged surfactants were added to the aqueous CMC solution. This is due to formation of an insoluble precipitate also known as coacervate. Turbidity was monitored by measuring the % transmittance of the solution at 420nm using a cell of 2.0 cm path length. Varying amount of the surfactant (from 0 to~3.5 m moldm -3 ) was added to a fixed amount of CMC (100µ mol dm -3, 3.0 ml). The result in case of pure surfactants is shown in Fig.6A and 6B.The ability of imparting turbidity was found to be in order: BDHAC>DDAB>CTAB>CPC>DPC. This is in accordance to their Critical Micellar Concentration values as shown in Table 2. Fig 6: Turbidimetric Titration of CMC (1 x 10-1 m mol dm -3, 3.0 ml) by cationic surfactants at 303 K. (A),DTAB and,ttab. Table 2: Values of binding constants of different cationic surfactants with CMC and their Critical Micellar Concentration values Surfactant CMC(m mol dm-3) 10-5Binding constant(mol-1 dm-3) BDHAC DDAB CTAB CPC TTAB DPC DTAB Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1867

9 CONCLUSION Studies on the interaction of CMC with PIN and AO were performed spectrophoto-fluorimetrically. Thermodynamic parameters for the dye-polymer interactions were found to be comparable with the reversible biological processes. The polymer quenched the fluorescence of AO. The present studies strongly revealed that the two forces, viz., electrostatic and hydrophobic forces are essentially involved during the aggregation process of polymer-dye. The binding ability of pure oppositely charged surfactants to the polymer CMC was found to be in accordance to their Critical micellar concentration values as observed in turbidemetric studies. The surfactant with lower Critical micellar concentration value required less concentration to impart turbidity to the CMC solution. ACKNOWLEDGMENT Authors are thankful to the Department of Chemistry, Tripura University for providing laboratory and computational facilities. REFERENCES 1. Lindman, B. &Thalberg, K.( 1993) Interaction of Surfactants with polymers and protins; Goddard, 2. E.D., Ananthapadmanabhan, K.P., Eds, CRC Press; Boca Raton, FL,. 3. Penfold, J., Taylar, D.J.F., Thomas, R.K., Tucker, I., & Thompson, L.J. (2003) Langmuir,19, Goddard, E.D., &Ananthapadmanabhan, K.P. (1993) Interaction of Surfactants with polymers andprotins; CRC Press; Boca Raton, FL. 5. Kwak, J.C.T. (1998) Polymer-Surfactant Systems; Surfactant Science Series; Marcel Dekker; New York. 6. Chakraborty, T., Chakraborty, I., &Ghosh, S. (2006) Langmuir, 22, Just, E.K., &Majewicz, T.G. (1985) Encyclopedia of polymer Science and Engineering; John Wiley and Sons; New York. 8. Romani. Ana, P., GehlenMareelo, H., &Rasangala, I. (2005) Langmuir, 21, Nath, R.K., Chakraborty, A., &Chakraborty, A.K (1987) J.Surface.Sci,Tech; 3, MacIntos, F.C. (1941) Bio Chem. J. 35, Pal, M.K. & Schubert, M. (1961) J.Phys. Chem. 65, Gummow, B.D. & Roberts, G.A.F. (1985) Macromol-Chem, 186, Mitra, A. &Chakraboty, A.K. (1998) Indian J. Biochem. Biophys., 35, Pal, M.K. & Schubert, M. (1961) J.Histochem. Cytochem., 9, Young, M.D., Phillops, G.O., &Balazs, E.A. (1967) Biochem; Biophys, Acta ; 141, Shweiter, B., Zanette, D., &Itre, R. (2004) J.Colloid Interface Sci., 278, 285 Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1868

10 17. Dasgupta, S., Nath, R.K., Biswas, S., Hossain, J., Mitra, A., & Panda, A.K. (2007) Colloids Surf., APhysicochem. Eng. Asp., 302, Chakraborty, A., Nath, R.K., &Chakraborty, A.K. (1989) SpectroChimicaActa A; 45, Pal, M.K., Ghosh, J.K., & Das, S. (1989) Ind.J. Bio Chem and Bio Phys., 26, Mitra, A., Nath, R.K., Biswas, S., Chakraborty, A.K., & Panda, A.K. (2006) J. Photochem.Photobiol., A Chem., 178, Anunnso, C.I. (1988) J.Ind. Chem. Soc. 65, Datta, G., Gurnani, S., Sen, G., &Mulchandani, N.B. (1981) J.Ind.Chem.Soc; 58, Von Berlepsch, H., Kirstein, S., &Bottcher, C. (2002) Langmuir, 18, Rose, N.J. &Drago, R.S., (1959) J. Am. Chem. Soc., 81, Dasgupta, S., Nath, R.K., Biswas, S., Mitra, A., & Panda, A.K., (2009) Indian J. Biochem. Biophys., 46, Panda, A.K. &Chakraboty, A.K. (1997) J. Photochem. Photobiol., A Chem., 111, Ganguly, B., Nath, R.K., Hussain, S.A., & Panda, A.K. (2010) Indian J. Phys., 84, 653. Banti Ganguly, R.K. Nath IJSRE Volume 2 Issue 9 September 2014 Page 1869

A spectroscopic study of interaction of cationic dyes with heparin

ISSN 1984-6428 ONLINE www.orbital.ufms.br Full Paper Orbital 2009, 1 (4), 255-272 A spectroscopic study of interaction of cationic dyes with heparin R. Nandini a *, B. Vishalakshi b a Department of Chemistry,