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Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior.
J Nanosci Nanotechnol. 2008 Apr; 8(4):1842-51.JN

Abstract

The melt rheology of polyaniline (PANI)-dinonylnaphthalenedisulfonic acid (DNNDSA) gel nanocomposites (GNCs) with organically modified (modified with cetyl trimethylammonium bromide)-montmorillonite (om-MMT) clay has been studied for three different clay concentrations at the temperature range 120-160 degrees C. Field emission scanning electron microscopy (FE-SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dc-conductivity data (approximately 10(-3) S/cm) indicate that the PANI-DNNDSA melt is in sol state and it is not de-doped at that condition. The WAXS data indicate that in GNC-1 sol clay tactoids are in exfoliated state but in the other sols they are in intercalated state. The zero shear viscosity (eta0), storage modulus (G') and loss modulus (G") increase than that of pure gel in the GNCs. The pure sol and the sols of gel nanocomposites (GNCs) exhibit Newtonian behavior for low shear rate (< 6 x 10(-3) s(-1)) and power law variation for the higher shear rate region. The characteristic time (A) increase with increasing clay concentration and the power law index (n) decreases with increase in clay concentration in the GNCs indicating increased shear thinning for the clay addition. Thus the sols of om-clay nanocomposites of PANI-DNNDSA system are easily processible. The storage modulus (G') of GNC sols are higher than that of pure PANI-DNNDSA sol, GNC1 sol shows a maximum of 733% increase in storage modulus and the percent increase decreases with increase in temperature. Exfoliated nature of clay tactoids has been attributed for the above dramatic increase of G'. The PANI-DNNDSA sol nanocomposites behave as a pseudo-solid at higher frequency where G' and loss modulus (G") show a crossover point in the frequency sweep experiment at a fixed temperature. The crossover frequency decreases with increase in clay concentration and it increases with increase in temperature for GNC sols. The pseudo-solid behavior has been explained from jamming or network formation of clay tactoids under shear. A probable explanation of the two apparently contradictory phenomena of shear thinning versus pseudo-solid behavior of the nanocomposite sols is discussed.

Authors+Show Affiliations

Garai A
Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
Nandi AK
No affiliation info available

MeSH

Aluminum SilicatesAniline CompoundsBentoniteClayCrystallizationElasticityMacromolecular SubstancesMaterials TestingMolecular ConformationNanostructuresNanotechnologyNaphthalenesParticle SizePhase TransitionShear StrengthSulfonic AcidsSurface PropertiesViscosity

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18572585

Citation

Garai, Ashesh, and Arun K. Nandi. "Rheology of Polyaniline-dinonylnaphthalene Disulfonic Acid (DNNDSA) Montmorillonite Clay Nanocomposites in the Sol State: Shear Thinning Versus Pseudo-solid Behavior." Journal of Nanoscience and Nanotechnology, vol. 8, no. 4, 2008, pp. 1842-51.
Garai A, Nandi AK. Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior. J Nanosci Nanotechnol. 2008;8(4):1842-51.
Garai, A., & Nandi, A. K. (2008). Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior. Journal of Nanoscience and Nanotechnology, 8(4), 1842-51.
Garai A, Nandi AK. Rheology of Polyaniline-dinonylnaphthalene Disulfonic Acid (DNNDSA) Montmorillonite Clay Nanocomposites in the Sol State: Shear Thinning Versus Pseudo-solid Behavior. J Nanosci Nanotechnol. 2008;8(4):1842-51. PubMed PMID: 18572585.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior. AU - Garai,Ashesh, AU - Nandi,Arun K, PY - 2008/6/25/pubmed PY - 2008/7/23/medline PY - 2008/6/25/entrez SP - 1842 EP - 51 JF - Journal of nanoscience and nanotechnology JO - J Nanosci Nanotechnol VL - 8 IS - 4 N2 - The melt rheology of polyaniline (PANI)-dinonylnaphthalenedisulfonic acid (DNNDSA) gel nanocomposites (GNCs) with organically modified (modified with cetyl trimethylammonium bromide)-montmorillonite (om-MMT) clay has been studied for three different clay concentrations at the temperature range 120-160 degrees C. Field emission scanning electron microscopy (FE-SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dc-conductivity data (approximately 10(-3) S/cm) indicate that the PANI-DNNDSA melt is in sol state and it is not de-doped at that condition. The WAXS data indicate that in GNC-1 sol clay tactoids are in exfoliated state but in the other sols they are in intercalated state. The zero shear viscosity (eta0), storage modulus (G') and loss modulus (G") increase than that of pure gel in the GNCs. The pure sol and the sols of gel nanocomposites (GNCs) exhibit Newtonian behavior for low shear rate (< 6 x 10(-3) s(-1)) and power law variation for the higher shear rate region. The characteristic time (A) increase with increasing clay concentration and the power law index (n) decreases with increase in clay concentration in the GNCs indicating increased shear thinning for the clay addition. Thus the sols of om-clay nanocomposites of PANI-DNNDSA system are easily processible. The storage modulus (G') of GNC sols are higher than that of pure PANI-DNNDSA sol, GNC1 sol shows a maximum of 733% increase in storage modulus and the percent increase decreases with increase in temperature. Exfoliated nature of clay tactoids has been attributed for the above dramatic increase of G'. The PANI-DNNDSA sol nanocomposites behave as a pseudo-solid at higher frequency where G' and loss modulus (G") show a crossover point in the frequency sweep experiment at a fixed temperature. The crossover frequency decreases with increase in clay concentration and it increases with increase in temperature for GNC sols. The pseudo-solid behavior has been explained from jamming or network formation of clay tactoids under shear. A probable explanation of the two apparently contradictory phenomena of shear thinning versus pseudo-solid behavior of the nanocomposite sols is discussed. SN - 1533-4880 UR - https://www.unboundmedicine.com/medline/citation/18572585/Rheology_of_polyaniline_dinonylnaphthalene_disulfonic_acid__DNNDSA__montmorillonite_clay_nanocomposites_in_the_sol_state:_shear_thinning_versus_pseudo_solid_behavior_ DB - PRIME DP - Unbound Medicine ER -