No abstract

A series of novel polymers have been prepared by free radical solution polymerization of a variety of hydrocarbon monomers with the (perfluoroalkyl)ethyl methacrylate monomer H2CC(CH3)CO2(CH2)2(CF2) n F, 1 (n̄ ≈ 7.7). Polymers prepared using two different methods of feeding 1 into the reaction mass are discussed. Through a judicious choice of reaction conditions, some control of polymer architecture was exhibited. The resultant (perfluoroalkyl)ethyl methacrylate-containing acrylic polymers were shown to be quite surface active in the solid state. The magnitude of surface activity depends on the monomer 1 feed method. The polymers were formulated into thin films and applied to a variety of surfaces. With levels at 1.5 wt % of 1, water and oil repellent surfaces were created. Water contact angles (advancing) of ∼80−115° and hexadecane contact angles (advancing) of ∼60−70° were observed routinely. In addition, it was observed that the concentration profile of fluorine in the films exhibited a steep gradient normal to the surface when studied by angle-dependent ESCA and secondary ion mass spectroscopic depth profiling.

Composition measurements of Cu–Ni and Au–Pd alloy surfaces annealed at 600 °C and under steady-state bombardment conditions are reported. A unique procedure for studying the effects of enhanced diffusion is employed. The ion-bombardment-induced alteration of the composition of the near surface region of a Cu–Ni, Ag–Au, and Au–Pd alloy has been studied between 200 ° and 550 °C. The results have been extrapolated to lower temperatures and used to explain conflicting reports of differential sputtering in these alloys.

A method for the analysis of lndole-3-acetic acid (IAA) in (23), and GC coupled with mass spectrometry (2,11,24). In most instances the GC methods require extensive purification of the plant extracts, derivative formation for volatility, and selective detectors. Although the absolute sensitivity of the GC and GC-MS methods is very high, the total sample sensitivity is often limited by the size of the sample injectable into the instruments. The high cost of GC-MS instrumentation makes these methods out of range for routine analysis by most workers.A sensitive spectrofluorometric assay for IAA was proposed (15,29) in which IAA is converted to indole-a-pyrone by a reaction with acetic anhydride and trifluoroacetic acid. An evaluation of the assay (7) Radioimmuno techniques are useful in assays of proteins, drugs and related hormones; however, the IAA molecule may be too small a hapten to impart specificity and sensitivity to the radioimmunoassay (9).The possible utility of HPLC for the determination ofcytokinins in plant extracts was suggested (18) and HPLC was used for the separation and/or determination of plant hormones (3,5,6,20,32). The HPLC-UV254 detector used to determine ABA levels (20, 32) detected ng quantities from a wide variety of plant extracts; however, the determination of IAA is complicated by the low A of IAA at 254 nm and the difficult separation of IAA from other plant components. This report outlines the conditions for the HPLC separation of IAA using several column-mobile phase systems and two sensitive, selective detectors for the quantitation of IAA in plant extracts. The HPLC method has been used to determine the IAA level in various plant tissues and these are compared with published data. The plant parts were dissected, weighed, frozen in liquid N2, and stored at -40 C until extraction for IAA analysis. MATERIALS AND METHODSPreparation of Plant Extracts. All reagents and solvents were ACS grade. The ether was further purified by passing through an aluminum oxide (Woelm, basic) column just before use. The over-all scheme for the extraction of free IAA, and the clean-up, was similar to that outlined (32). Plant material (0.1-5 g) was removed from the freezer and extracted in a blender with 75 ml of cold 80% methyl alcohol, to which was added a known aliquot of 3-indolyl [1-_4C]