Search results for "Thermal transition"
showing 2 items of 2 documents
Indication of an order-order-transition by a partial disordering in ABC-triblock copolymers
1996
Poly(ethylene-alt-propylene)-block-polyethylethylene-block-polystyrene (PEP-b-PEE-b-PS) triblock copolymers were synthesized by anionic polymerization and subsequent hydrogenation of poly-1,4-isoprene-block-poly-1,2-butadiene-block-polystyrene triblock copolymers (1,4PI-b-1,2PB-b-PS). Differential scanning calorimetry and dynamic mechanical spectroscopy reveal an order-order transition which is induced by the mixing of PEP and PEE above their respective order-disorder transition (ODT).
Insights into catanionic vesicles thermal transition by NMR spectroscopy
2012
Oppositely charged ionic surfactants can self-assemble into hollow structures, called catanionic vesicles, where the anionic-cationic surfactant pair assumes a double-tailed zwitterionic attitude. In the present work, multilamellar- to-unilamellar thermal transition of a mixed aqueous system of sodium dodecyl sulphate (SDS) and cetyl trimethyl ammonium bromide (CTAB), with a slight excess of the anionic one, has been investigated by 1H, 2H, 14N NMR spectra and 23Na transverse relaxation measurements. It has been inferred that an increase of the temperature enhances the SDS counterion dissociation, which can be considered as one of the driving forces of the mentioned transition. Moreover, in…