Binding of Methylene Blue to Polyelectrolytes Containing Sulfonate Groups

Abstract

The interaction between methylene blue (MB) and poly(sodium 4‐styrenesulfonate) (PSS), poly(sodium vinylsulfonate) (PVS), and the more hydrophobic poly[sodium 2‐(N‐acrylamido)‐2‐methyl‐propanesulfonate] (PAMPS), is investigated. The main driving forces for the interaction with PSS are supposed to be short‐range aromatic/aromatic interactions, which explain the smaller dissociation constant, the resistance to the cleaving effect of NaCl, and the prevention of MB self‐aggregation around the macromolecules under a moderate excess of the polymer. On the contrary, as a consequence of long‐range interactions, a higher local concentration of MB around PAMPS and, more significantly, around PVS results in MB self‐aggregation that can be quenched in the presence of NaCl.magnified image

Association Efficiency of Three Ionic Forms of Oxytetracycline to Cationic and Anionic Oil-In-Water Nanoemulsions Analyzed by Diafiltration

“…19,20 However, for organic counterions, deviations from expected results have been reported, ascribed to the occurrence of site-specific short-range interactions. [24][25][26][27][28] Indeed, the hydrocarbon nature of organic counterions and their structure may produce hydrophobic interactions related with the amphiphilia of the LMWS, and secondary short-range interactions such as short-range electrostatic interactions, hydrogen bonding, and aromatic-aromatic interactions that change the interaction patterns, producing site-specific binding, higher binding constants, specific molecular geometries and architectures, and even binding of like-charged molecules. [24][25][26][28][29][30][31] In particular, aromatic-aromatic interactions may easily produce ion pairs of high hydrophobia that may be stabilized in a hydrophobic environment, 32,33 affecting the partition coefficient.…”

“…[43][44][45] Complex mixtures are filtered through a membrane, which has pores that discriminate between species according to their molecular size. In addition, as a separation technique, DF has emerged as an effective technique to study interactions between LMWS and several macromolecular species including soluble polymers, [25][26][27][28][30][31][32][33][34][46][47][48][49][50] polymeric nanoparticles, 51,52 antibodies, 53 and food matrices, 54 among others. The membrane pore size may be chosen so that only the passage of free LMWS is allowed.…”

Unusual Stepwise Protonation and J‐Aggregation of meso‐Tetrakis(N‐methylpyridinium‐4‐yl)porphine on Binding Poly(sodium vinylsulfonate)

“…Poly(sodium vinylsulfonate) (PVS), completely dissociated from its counterion in aqueous solution, represents an efficient and versatile highly charged polyanion template for binding various species exclusively through electrostatic self‐assembly. In literature some examples concern a large variety of cationic species, as pseudo‐isocyanine dyes (PIC),10 [Ru(bpy) 3 ] 3+ (bpy=2,2′‐ bipyridine),11 2,3,5‐triphenyl‐2H‐tetrazolium chloride (TTC),12 methylene blue (MB),13 Safranine T,14 as well as neutral molecules like the antihistaminic drug chlorpheniramine maleate (CPM) 15. The close proximity of negatively charged sulfonic groups can influence the aggregation properties of the bound chromophores, promoting for example, in the case of PIC dyes, the formation of J‐aggregates 10.…”

Carrageenan-grafted magnetite nanoparticles as recyclable sorbents for dye removal

“…Indeed, in our recent work devoted to the study of the removal of MB using magnetic nanoparticles with j-carrageenan molecules adsorbed onto the surface we have also reported this unusual type of adsorption isotherm (Salgueiro et al 2013). This behavior was attributed to the formation of MB aggregates in MB concentrated solutions, which can cause the disruption of the carrageenan network by electrostatic interaction with the sulfonated polyelectrolytes, thus exposing to the solution sulfonate groups that were not available before (Moreno-Villoslada et al 2009;Salgueiro et al 2013).…”