Interactions between charged polypeptides and nonionic surfactants.

The influence of molecular characteristics on the mutual interaction between peptides and nonionic surfactants has been investigated by studying the effects of surfactants on amphiphilic, random copolymers of alpha-L-amino acids containing lysine residues as the hydrophilic parts. The hydrophobic residues were either phenylalanine or tyrosine. The peptide-surfactant interactions were studied by means of circular dichroism spectroscopy and binding isotherms, as well as by 1D and 2D NMR.

Thermotropic phase behaviour of long-chain alkylmaltosides.

The thermotropic phase behaviour and phase structure of crystalline and non-crystalline n-tetradecyl-beta-D-maltoside (C14G2) and n-hexadecyl-beta-D-maltoside (C16G2) have been investigated by means of differential scanning calorimetry and X-ray techniques. Upon lyophilisation, both compounds form a solid, lamellar phase comprising disordered head groups and hexagonally packed alkyl chains that are suggested to be tilted and interdigitated. This ordered lamellar phase melts into a metastable lamellar liquid crystal, which re-crystallises to a high-temperature crystalline polymorph comprising interdigitated, non-tilted alkyl chains.

Solid-state phase behaviour of dodecylglycosides.

The solid-state phase behaviour of lyophilised n-dodecyl-beta-D-glucoside (beta-C(12)G(1)), n-dodecyl-beta-D-maltoside (beta-C(12)G(2)) and n-dodecyl-beta-D-maltotrioside (beta-C(12)G(3)) has been investigated by differential scanning calorimetry (DSC) and X-ray techniques. For beta-C(12)G(1), lyophilisation results in a formation of a crystalline anhydrate. The lamellar spacing (37 Angstroms) is consistent with an alkyl chain packing in which the chains are not interdigitated.

Effects of temperature, salt, and deuterium oxide on the self-aggregation of alkylglycosides in dilute solution. 1. n-nonyl-beta-D-glucoside.

The influence of salt, temperature, and deuterium oxide on the self-aggregation of n-nonyl-beta-D-glucoside (beta-C9G1) in dilute solution has been investigated by static and dynamic light scattering, neutron scattering, and tensiometry. Scattering data show that the micelles can be described as relatively stiff, elongated structures with a circular cross section. With a decrease of temperature, the micelles grow in one dimension, which makes it surprising that the critical micelle concentration (cmc) shows a concomitant increase.

Effects of temperature, salt, and deuterium oxide on the self-aggregation of alkylglycosides in dilute solution. 2. n-Tetradecyl-beta-D-maltoside.

The effects of salt, temperature, and deuterium oxide on the self-aggregation of n-tetradecyl-beta-d-maltoside (C(14)G(2)) in dilute solution have been investigated by static light scattering, dynamic light scattering (DLS), small-angle neutron scattering (SANS), tensiometry, and capillary viscometry. SANS data show that the micelles can be described as relatively flexible polymer-like micelles with an elliptical cross section, at least at temperatures between 35 and 50 degrees C. The micelles grow in one dimension with increasing temperature and concentration.