Nanoscopic structure of a metallo-supramolecular polyelectrolyte-amphiphile complex, elucidated by x-ray scattering and molecular modeling

A combination of molecular modeling and X-ray scattering was used to elucidate the structure of the metallosupramolecular polyelectrolyte-amphiphile complex (PAC) self-assembled from Fe-II, 1,2-bis(2,2':6',2''-terpyridin-4'-yl)benzene, and dihexadecyl phosphate (DHP). An approximate structure of the semi-ordered material was derived from the analysis of the X-ray scattering data. The experimental data provided sufficient input for obtaining a useful starting configuration for molecular modeling. Various models of the supramolecular architecture are presented and discussed in terms of their total energies and scattering patterns. In an iterative approach each level of the structural hierarchy was refined until satisfactory agreement of calculated and experimental scattering patterns was reached. The remarkable sensitivity of the simulated scattering curves to even the smallest structural changes at all length scales restricts the arbitrariness of modelling. The final model of PAC consists of flat lamellae of alternating strata of interdigitated DHP monolayers and nematically ordered polyelectrolyte chains

Polyampholyte-dressed micelles of fluorinated and hydrogenated dodecanoic acid

Polyampholytes with alternating cationic and anionic monomers were synthesized and complexed with fatty acids (dodecanoic acid and perfluorododecanoic acid). The formation of the polyelectrolyte-fatty acid complexes is self-assembled and generates nanoparticles with sizes in the range of 3-5 nm that were named dressed micelles. A defined arrangement of the ionic charges of three polyampholytes was achieved by the copolymerization of a cationic vinyl monomer (N,N'-diallyl-N'N-dimethylammonium chloride) and anionic vinyl monomers (maleamic acid, phenylmaleamic acid, and 4-butylphenylmaleamic acid). The zeta potentials of the polyampholyte dressed micelles were adjusted in the range of -56 to 25 mV. They increase when replacing the alkylated dodecanoic acid by its perfluorinated counterpart, and they also increase when enhancing the hydrophilicity of the polyampholyte. Analytical ultracentrifugation, dynamic light scattering, and isothermal titration calorinietry were used for the characterization of the fluorinated and the hydrogenated complexes

Structure of a liquid crystalline metallosupramolecular polyelectrolyte-amphiphile complex at the nanoscopic level

The solid-state organization of a liquid crystalline metallosupramolecular polyelectrolyte-amphiphile complex at the nanoscopic level is decoded by a combination of X-ray scattering and molecular modeling. The nanostructured material, which self-assembles from transition metal ions, ditopic ligands, and amphiphiles, has a hierarchical architecture consisting of alternating strata of metallo units and interdigitated amphiphiles

Complexes of poly(ethylene oxide)-block-poly(L-glutamate) and diminazene

Nanoparticles with a mean hydrodynamic radius of 16 run and low polydispersity (P.I. = 0. 1) were spontaneously formed by the complexation of poly(ethylene oxide)-block-poly(L-glutamate) (PEO-b-PLGlu) with diminazene. Only one of two possible binding sites of each diminazene molecule was involved in complexation. As determined by UV-vis difference spectra measurements. the complex binding constant is on the order of 1-2 x 10(4) M-1. Circular dichroism measurements showed that the highly water-soluble diminazene can induce and stabilize the cc-helical secondary structure of a PLGlu block