Substrat mit gering lichtstreuender, ultraphober Oberflaeche und Verfahren zu seiner Herstellung

DE 10026299 A UPAB: 20020402 NOVELTY - An ultraphobic substrate has a total scattered light loss of at most 7 ( at most 1)% and a contact angle with water at least 140 (especially at least 150) deg. . DETAILED DESCRIPTION - Also included is an INDEPENDENT CLAIM for identification of process conditions and production of suitable surfaces comprising: (a) determining the refractive index of the individual coating layers for a number of substrates which have been selected with respect to the thickness and sequence of the coating layers; (b) calculating the total scattered light loss for various surface topographies and selecting those with a loss of at most 7 (especially at most 1)%; (c) selecting the topographies for ultraphobic properties using the expression Slog(f) = a(f).f such that the integral of the function Slog(f) is at least 0.3 between the limits log(f1/ mu m1) = -3 and log(f2/ mu m1) = 3 (PCT/99/10322 (WO0039240); (d) ensuring that the coating process is such that conditions (b) and (c) are fulfilled in series or (especially) parallel; (e) determining the total scattering loss and the contact angle; and (f) identifying the cases in which the contact angle at least 140 (especially at least 150) deg. and the total scattered light loss at most 7 ( at most 1)%. USE - Claimed uses are as (a) transparent screens (eg windows) or cover layers for such screens (especially of glass or plastics) for use in solar cells, vehicles aircraft or houses; and (b) non-transparent external elements for buildings, vehicles or aircraft. ADVANTAGE - Substrates are provided which combine low light scattering with ultraphobicity

Molecular weight dependent fragmentation of selectively deuterated polystyrenes in ToF-SIMS

Two series of monodisperse polystyrenes were synthesized by an anionic polymerization initiated with sec-butyllithium. The number average molecular weights of the macrochains range from 1700 to 93300. The first series consist of deuterated repeat units and hydrogenated end groups (sec-PD8S-H). The other one was fully hydrogenated except for one end group, which was selectively deuterated (sec-PS-D). The sample molecular structures are C4H9(C8D8)(n)H and C4H9(C8H8)(n)D, respectively. These polymers were then analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). All secondary ion intensities are corrected for the carbon and deuterium isotopic distributions. Static SIMS spectra of sec-PD8S-H show characteristic peaks with even masses (fully deuterated, i.e., C7D7+, C6D5+ at m/z = 98, 82) and odd peaks (containing at least one hydrogen atom, i.e., C7HD6+, C6HD4+ at m/z = 97, 81). Typically, these odd peaks show decreasing intensities as the molecular weight increases. In the sec-PS-D SIMS spectra, the characteristic peaks are similar to those observed for the usual polystyrene with a more specific peak at m/z = 92 which is related to the deuterium end group. From the molecular weight dependent intensities, it can be deduced that a hydrogen transfer occurs from the sec-butyl end group to the first repeat unit and promotes the formation of the tropylium fragment. A rearrangement ion formation mechanism is proposed. For both polymers, characteristic peaks of the end group are detected. With the intensity ratios of a main chain fragment and these end groups characteristic peaks, we are able to calibrate the number average molecular weight at the polymer surface. Moreover, it is shown that the main chain deuteration influences the end group segregation toward the surface