Thermal patterning of a critical polymer blend.

Utilizing the Soret effect, we have employed a moderately focused laser beam (30 microm, 20 mW) to write spatial composition patterns into layers of the critical polymer blend poly(dimethyl siloxane)/poly(ethyl-methyl siloxane) (PDMS/PEMS, M(w)=16.4/22.8 kg/mol) both in the one- and in the two-phase region a few degrees above and below the critical temperature T(c)=37.

Correlation between the Soret coefficient and the static structure factor in a polymer blend.

Mutual mass diffusion and thermal diffusion has been investigated in poly(dimethylsiloxane)/poly(ethylmethylsiloxane) (PDMS/PEMS) polymer blends of equal weight fractions. Molar masses ranged from below 1 to over 20 kg/mol. Both the mutual mass (D) and the thermal diffusion (D(T)) coefficient contain a thermally activated factor with an activation temperature of 1415 K.

Energy spectra of geomagnetically trapped oxygen ions.

In a series of COSMOS satellite flights plastic nuclear track detectors have been exposed in low-earth orbits to monitor anomalous cosmic rays (ACR) at energies below 25 MeV/nuc. The analysis of energy spectra has now been extended to energies up to 40 MeV/nuc for two exposures aboard COSMOS 2260 in 1993 and COSMOS 2311 in 1995. Our data on trapped ACR (TACR) oxygen energy spectra might indicate the influence of energy-dependent stripping probabilities and the presence of multiply charged ACR oxygen at high energies as reported by latest SAMPEX observations.