Characterization of the complexes of amphiphilic polyanions and double-chain cationic surfactants

Abstract

Coulombic complexes of amphiphilic polyanions and double-chain cationic surfactants were prepared by adding an aqueous solution of didodecyldimethylammonium bromide (DDAB) to aqueous solutions of terpolymers consisting of sodium 2-(acrylamido)-2-methylpropanesulfonate, 7V-(l-adamantyl)methacryIamide (49 mol %) or N-(l-naphthylmethyl)methacrylamide (59 mol %), and JV-(l-pyrenylmethyl)methacrylamide (1 mol %). As the contents of the adamantyl and naphthyl groups in the terpolymers are sufficiently high, the parent terpolymers adopt micellelike microphase structures in aqueous solution. Both the complexes of the adamantyl and naphthyl terpolymers with DDAB were soluble in benzene, methanol, tetrahydrofuran (THF), acetonitrile (ACN), IV^V-dimethylformamide (DMF), etc.NMR spectra indicated that the quantitative numbers of DDAB were ionically bound to the sulfonate sites in the parent terpolymers. Dynamic light scattering data for the complex of the adamantyl terpolymer showed that the size of the complex in THF solution ranged from 6 to 15 nm in diameter, which fairly agreed with a radius of gyration estimated on the basis of GPC data.NMR spectra, 2D-NOESY, and spin-lattice and spin-spin relaxation times for the complex of the naphthyl terpolymer in organic solution revealed that the motions of the naphthyl residues were highly restricted, while those of the DDAB residues were much less restricted. These findings imply that the micellelike microphase structure of the parent amphiphilic polyanions formed in aqueous solution remained rather intact in the complexes even though they were dissolved in organic solvents. In benzene solution, the complex was shown to be in a particularly compact form. Fluorescence emitted by the pyrenyl probes incorporated in the complexes supported these findings.

Spontaneous Vesicle Formation in Aqueous Mixtures of Cationic Surfactants and Partially Hydrolyzed Polyacrylamide

“…Table 2 shows the conditions of vesicle formation in the mixed cationic surfactant and HPAM with various hydrolysis degree systems. Unlike the C 12 NMBr-30% hydrolyzed polyacrylamide system, no vesicles were found in the mixed systems of C 12 degree. Thus the size of the hydrophobic area relative to hydrophilic area in the complex will be also reduced, greatly decreasing the vesicle forming ability in these systems.…”

Poly(n-butyl acrylate-co-methyl methacrylate) and poly(n-butyl acrylate-co-styrene)/ silicate nanocomposites prepared by emulsion polymerization

“…n-butyl acrylate (BA), methyl methacrylate (MMA), styrene (ST), dodecylbenzenesulfonic aicd sodum salt (DBS-Na), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) [18][19][20] were purchased from Aldrich and used as received. The silicate used in this paper was sodium montmorillonite (Na-MMT) of Kunipia-F purchased from Kunimine Co. and the silicate had 119 mequiv/100 g of cation exchange capacity.…”

Synthesis and properties of exfoliated poly(methyl methacrylate-co-acrylonitrile)/ clay nanocomposites via emulsion polymerization

“…24,25 We will extend this method to copolymerization of MMA and AN and describe a simple and convenient way to obtain exfoliated P(MMA-co-AN)/ Na-MMT nanocomposites through in-situ polymerization with 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) 26 in presence of pristine Na-MMT.…”