Preferential interactions of poly(N-vinyl-2-pyrrolidone) in the binary mixture water/CdCl2 (original) (raw)
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European Polymer Journal, 1997
Abatract-In this paper, the morphologyof poly(N-vinyl-2-pyrrolidone) (PVP)in the presenceof NazMoO, has beenstudiedusingscanningelectronmicroscopy (SEM).Moreover the poly(N-vinyl-2pyrrolidone) (PVP)(2)/water(l)/NaJvlo0,(3)ternarysystemhas beencharacterized by viscometry and densimetry. Alattice-like tridimensional structureofPVPdue to its interactionwithNa,MoO, is observed. In this ternary system both a preferential adsorption of water at all solvent compositions studied is observed, except at 100mM of NazMo04, concentration at whicha preferential adsorptionof salt is exhibited. Na2Mo0, behaves asa salting-in agentforthemacromolecule, thebinarysolvent mixturebeing thermodynamically unfavorableat salt concentrations largerthan 10mMNalMoO,.CO1997Elsevier ScienceLtd. All rights reserved 10.
Polymer, 2000
The solvation of 1-vinyl-2-pyrrolidone and poly(1-vinyl-2-pyrrolidone) in solvents of varying polarity, specifically water, ethylene glycol, chloroform and carbon tetrachloride, was investigated by means of Fourier transform infrared (FT-IR), FT-Raman, UV, 1 H and 13 C NMR spectroscopy. The IR and Raman measurements made it possible to establish the structures of the solvated molecules and the type of the hydrogen bonding that was obtained. From the UV results, the strength of the vinyl double bond was estimated in the different solvents. The 1 H and 13 C NMR spectra indicated that polar solvents interact with the solutes at the carbonyl group of the pyrrolidone ring, whereas nonpolar solvents interact mainly with the vinyl group in the 1-vinyl-2-pyrrolidone and with the polymer chain in poly(1-vinyl-2-pyrrolidone).
Interaction between Cetyl Pyridinium Chloride and Water-Soluble Polymers in Aqueous Solutions
Journal of Colloid and Interface Science, 1997
takes place when the surfactant concentration is higher than a The interaction between cetyl pyridinium chloride and differentvalue termed the critical aggregation concentration (CAC). molecular-weight poly(vinylpyrrolidone) (PVP) and poly(ethyl-Then, there is binding of the surfactant onto the polymer in ene glycol) (PEG) polymers has been investigated by means of the form of aggregates (1). Once the polymer is saturated electrical conductivity and fluorescence probing. No interaction with the surfactant, the excess of surfactant molecules forms between the low-molecular-weight PVP polymers and the surfacfree micelles and at higher surfactant concentrations polytant was detected, whereas a significant interaction was observed mer-bound aggregates coexist with free micelles. between high-molecular-weight PVP polymers or PEG polymers In polyelectrolyte oppositely charged surfactant systems, and cetyl pyridinium chloride. The results indicate that polymerthe interaction clearly results from strong coulombic forces. surfactant aggregates start to form at a surfactant concentration higher than the critical micelle concentration of micelles without In contrast to nonionic polymer systems, the interaction leads polymers. In contrast, the degree of ionization and the interface to phase separation. This fact limits the studies to surfactant polarity decrease as compared with values of micelles without concentrations close to the critical micelle concentration polymers. The Gibbs free energy associated with the interaction (CMC). The interaction begins at surfactant concentrations was also calculated. The values show that the addition of polymers below the CMC of the pure surfactant. At high polyelectrostabilizes polymer-surfactant aggregates. ᭧ 1997 Academic Press lyte concentrations a second, gel-like, liquid phase starts to Key Words: cetyl pyridinium chloride; poly(vinylpyrrolidone); form and can be separated at surfactant concentrations much poly(ethylene glycol); pyrene 1-carboxaldehyde; polymer-surfaclower than those corresponding to charge neutralization. The tant interaction; electrical conductivity; fluorescence probing. phase behavior (10) and surfactant aggregation number (11) have been obtained for some surfactant-polyelectrolyte systems. 356
Langmuir, 2011
Complex formation between oppositely charged polyelectrolytes and surfactants has been an important subject of research for both fundamental and application reasons. 1À7 PolymerÀ surfactant mixtures are widely exploited in commonplace formulations to manipulate their performance behaviors. The ternary systems of surfactant, polymer, and water have potential for domestic, industrial, and technological applications, viz., foods, paints, drug delivery, coatings, laundry products, cosmetics, etc. 8,9 In such applications, polymers are mainly used as viscosity modifiers and stabilizers. Oppositely charged polymerÀ micellar aggregates can serve as models for polyionÀcolloid systems. 10 The Coulombic polyionÀcolloid interaction guides the flocculation of inorganic materials important in water purification. 11,12 Although the field is continuously being explored, information on combinations of different kinds is yet not adequate from the standpoint of fundamental understanding and applications.
Langmuir, 2002
The interaction of poly(vinyl caprolactam) (PVCAP) with sodium dodecyl sulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) in aqueous solutions has been studied systematically by measuring the phase separation temperature, hydrodynamic radius, pyrene solubility, and surfactant binding isotherms. Both surfactants were observed to elevate the solution cloud point of PVCAP and cause the polymer to undergo a coil to globule transition. This transition occurs at a concentration about 1 /10 of the critical micelle concentration (cmc) for SDS in the absence of polymer but at the cmc with DTAB. The results indicate that PVCAP interacts with SDS monomers but only with micelles in the case of DTAB. The phase behavior of the PVCAP/SDS/DTAB ternary system shows that the binding of SDS to PVCAP is reversible on changing the concentration of the free surfactant monomer in solution. Potentiometric titration of PVCAP and measurements of pyrene solubility in its mixtures with surfactants suggest that complexation of PVCAP and SDS is due to a combination of ion-dipole and hydrophobic effects. PVCAP and DTAB micelles interact through hydrophobic inclusion of polymer segments into the DTAB micelles. Pyrene is not solubilized by PVCAP in solution alone. Addition of SDS to PVCAP solutions induces marked pyrene solubilization well below the cmc, characterized by a region indicating saturation adsorption of the pyrene to the PVCAP/SDS complex. Above the SDS cmc, solubilization of pyrene increases linearly with SDS concentration, corresponding to inclusion of the pyrene into the SDS micelles. In contrast to SDS, the addition of DTAB to a solution of PVCAP shows no pyrene solubilization until the cmc is reached.
Journal of Applied Polymer Science, 2003
Viscosity and density studies for 0.01–0.14% (w/w) poly(N-vinyl-2-pyrrolidone) (PVP) in water and in water and 0.01% bovine serum albumin (BSA) were conducted at 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K. The viscosity coefficients and the activation-energy, free-energy, enthalpy, and entropy changes were calculated from viscosity data for viscous flow. On this basis, PVP–PVP, PVP–BSA, PVP–water, and BSA–water interactions and PVP and BSA shape factors were investigated and rationalized in terms of the water structure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1001–1015, 2003
Preferential adsorption in polymer/solvent-1 /solvent-2 solutions by infrared spectroscopy
British Polymer Journal, 1990
IR spectroscopy is shown to be a suitable technique for preferential adsorption studies in the following solvent-I/solvent-2/polynier systems: poly( Nvinylcarbazole) and polyacenaphthene in nitrobenzene/dioxane, nitrobenzene/ tetrahydrofuran, and nitrobenzene/cyclohexanone. Values of the prcfercntial adsorption parameters derived from the Schultz-Flory theory agree with those from IR when both solvents in the ternary system are considered to be good solvents for the polymer. In the systems studied, the relative adsorptions of solvent-1 and solvent-2 by the polymer depend on the solvent mixture composition. The number of adsorbed molecules and their performance are correlated with the ternary interaction parameters, x , ,~, and the Mark-Houwink-Sakurada exponent, a'. The adsorption changes observed are greater in those systems in which tetrahydrofuran was present.
Dipolar polymeric compounds and their properties in the aqueous medium
Reactive & Functional Polymers, 2007
Reactions between poly(4-vinylpyridine) and acrylic acid as well as poly(vinylimidazole) and the same acid led to polymers containing carboxybetaine repeating units with a percentage higher than 90%. Chemical structures and compositions of chemically modified polymers were established from their 1H NMR and IR spectra. The solution properties of the two poly(carboxybetaines) were analyzed by potentiometric titrations and viscometric measurements. Deionized water as well as CaCl2 and NaCl aqueous solutions of different concentrations were used as solvents. From potentiometric titrations with 0.5 M HCl, the apparent pKa values were determined using Henderson–Hasselbach equation. These values are strongly depended of the solvent nature. Thus, both poly(carboxybetaines) have the lowest pKa values when deionized water was used as solvent. Therefore, the lowest binding ability of the H+ by COO− groups occurs in this solvent.The viscometric measurements revealed that reduced viscosity values are non-responsive towards the polymer solution concentrations irrespective of the used solvent (i.e., deionized water or NaCl and CaCl2 aqueous solutions). Therefore, the behaviour of these carboxybetaine macromolecules in the above-mentioned solvents is that of hung up hard spheres. Consequently, the intrinsic viscosity values were calculated according to the Einstein–Simha equation applicable for such systems. The [η] versus salt solution concentration plots show a decreasing part in the concentration range from 0 to 0.05 M that is followed by a slow [η] increasing.In 0.5 M HCl both poly(carboxybetaines) exhibit the viscometric polyelectrolyte behaviours because of their shift to the corresponding cationic polyelectrolytes.
Journal of Membrane Science, 2004
The interaction of the water-soluble polymer poly(sodium 4-styrenesulfonate) with 2,3,5-triphenyl-2H-tetrazolium chloride is studied. Diafiltration experiments at pH 4, 7.5, and 10, and in the presence of NaNO 3 at different concentrations show weak interactions of the low molecular weight molecule and the polymer with apparent dissociation constants ranging between 0.6 and 6, and strong interactions, detectable in the absence of NaNO 3 , with apparent dissociation constants ranging between 0.04 and 0.2, if the effect of the interactions of the water-soluble polymer with the diafiltration cell components is neglected. Apart from hydrophobic forces this is attributed to both long-range and short-range electrostatic forces. The short-range interaction is reflected in UV-vis spectroscopic studies by a decrease on the intensity of the maximum at 248 nm.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1996
The simultaneous adsorption of lithium dodecyl sulfate (LiDS)/lithium perfluorooctanesulfonate (LiFOS) and poly(N-vinyl-2-pyrrolidone) (PVP) from PVP-LiDS and PVP-LiFOS binary mixed aqueous solutions on hydrophilic/ hydrophobic silica was investigated. The conformation and layer thickness of PVP adsorbed on silica were also estimated by using ESR and photon correlation spectroscopy (PCS), respectively. By introducing a sedimentation field-flow fractionation (sedFFF) separation step prior to the PCS sizing to fractionate the adsorbate into cuts of uniform particle size, it is possible to improve the accuracy in these size measurements. The adsorption of PVP is enhanced in the presence of LiDS at low LiDS concentration owing to the formation of a surface complex of PVP and LIDS, followed by a decrease at high LiDS concentration. However, this increment on hydrophobic silica is significantly greater than that on hydrophilic silica. A similar trend is also observed in the PVP-LiFOS system. In both the PVP-LiDS and PVP-LiFOS systems, the conformation of PVP adsorbed, in particular on hydrophilic silica, is changed remarkably from loops and tails to trains with the surfactant concentration. The results obtained from ESR show a good relationship with the thickness of PVP adsorbed obtained from PCS.