The distribution of polymer terminal groups at surfaces and interfaces is assessed by neutron reflectometry (NR) experiments on end-functional polystyrenes. Mono-terminated polystyrenes (PS) are synthesized anionically to include a short perdeuteriostyrene sequence adjacent to the end groups for the purpose of selective contrast labeling of the end groups for NR. The location of deuterium serves as a marker to indicate the location of the adjacent end group. Three cases of end group surface segregation are examined: a "neutral" control specimen prepared by proton termination, a "repulsive" end group system terminated with high surface energy carboxylic acid end groups, and an "attractive" end group system containing low surface energy fluorocarbon chain ends. All three systems exhibit damped oscillatory end group concentration depth profiles at both the air and substrate interfaces. The periods of these oscillations correspond approximately to the polymer chain dimensions. The surface structure of the "control" sample is dominated by the sec-butyl initiator fragment located at one end of the chain. This end group has a lower surface energy than that of the PS backbone and segregates preferentially to both the air and substrate interfaces. In the fluorosilaneterminated material, the low energy fluorinated end groups are depleted from the substrate interface but are found in excess at the air interface. In the carboxy-terminated material, the high energy carboxyl end group segregates preferentially to the silicon oxide overlayer on the substrate and is depleted at the air surface. X-ray photoelectron spectroscopy (XPS) is utilized surface compositions for the three systems.

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Self-organized rhodamine 6G (Rh6G) thin films on a glass substrate were prepared by spin-coating, dip-coating, and drop-coating. The thickness of the Rh6G layer strongly influences both the absorption and emission spectra, which are accounted for by monomers, exciton and excimer formation, and molecular aggregation. Submonolayer films of Rh6G show one maximum and one apparent shoulder in the absorption spectrum, but three peaks are required for deconvolution of the spectrum. As the thin film becomes thicker, the observed maximum shifts to lower energy, and a fourth peak is required for deconvolution. The emission spectra show similar features. In addition, the relative intensity of the emission is strongly dependent on the film thickness with thinner films being substantially more emissive than thick films.

The synthesis of high molecular weight star-shaped polymers comprising poly(1,3-cyclohexadiene) arms coupled to a divinylbenzene (DVB) core is reported. In-situ FTIR spectroscopy was used to verify first-order polymerization kinetics for 1,3-cyclohexadiene at 40 °C in cyclohexane with a 10 wt % monomer concentration using a tetramethylethylenediamine (TMEDA) to n-butyllithium (n-BuLi) ratio of 5/4. The propagation rate constant was determined to be 0.31 L mol-1 s-1. The degree of 1,2-addition (70%) vs 1,4-addition (30%) for 1,3-cyclohexadiene was determined using 1H NMR spectroscopy. The molecular weights of the preformed arms were 10 000 and 5000 g/mol, and the ratio of DVB to n-BuLi was systematically varied from 6:1 to 24:1. Gel permeation chromatography coupled with light scattering detection was utilized to detect the formation of star-shaped polymers and the presence of star−star coupling. In-situ spectroscopy and obvious color changes indicated that the addition of DVB to poly(1,3-cyclohexadienyllithium) was rapid. The molecular weight distribution (M w/M n) of the star polymers ranged from 1.4 to 1.9. The polymeric materials were thermally stable to 330 °C under a nitrogen environment. The refractive indices of both the homopolymers and star polymers were 1.572 at 600 nm and remained relatively constant from 1600 to 550 nm. The T g of the high molecular weight star-shaped polymers was 150 °C.