In-situ deposited thin films of the conducting polymer poly-3,4-ethylenedioxythiophene (PEDOT) have been prepared on hydrophilic and hydrophobic substrates and characterized by UV-Vis spectroscopy, atomic force microscopy and resistivity measurements.

High-resolution X-ray photoelectron spectroscopy (XPS) has been applied to a series of free-base and Zn-porphyrin polymers in which the macrocycles are separated by oligo(phenylene vinylene) units (OPV) of different, controllable lengths. Neat films of all the Zn-porphyrin polymers unexpectedly reveal two peaks in the N 1s XPS region ( approximately 400 eV). The peak areas vary with the length of the OPV bridge, suggesting an intermolecular interaction between the porphyrin and linker subunits. A series of XPS analyses were performed to identify the different interactions taking place in these thin films. To inhibit interpolymer interactions, one of the polymers was incorporated into a nonconjugated PMMA matrix, collapsing the N1s spectrum to a single peak at 398.0 eV, relative to the neat film signals at 397.8 and 400.1 eV. In a conjugated matrix of OPV, two peaks remain at 401.7 and 399.5 eV. Extensive vacuum drying of the neat film leads to a single peak at 398.3 eV, suggesting loss of trapped solvent molecules. Ultimately, we attribute the lower energy signal of the neat films to solvent ligation, and the higher energy peak is attributed to interactions between the porphyrins and conjugated bridges on nearby polymer chains. This interpretation is successfully applied to the N 1s XPS data from a previously reported Zn-porphyrin oligomer-based multilayer array.

A combination of oligomeric porphyrin copolymers and bidentate Lewis bases has been used to construct 2-dimensional multilayer molecular architectures on siloxane-derivatized glass substrates. The key to this supramolecular chemistry is coordinate covalent bonding between zinc-metalated porphyrins and bipyridyl "spacer" ligands, generating layers in an alternating, iterative fashion. UV-vis, XPS, AFM, and X-ray diffraction data support the formation of ordered thin film arrays. The stepwise deposition of each porphyrin layer is tracked by the linear increase in the absorbance of the porphyrin Soret band. XPS results demonstrate that the pyridinium coupling in the first monolayer is susceptible to X-ray decomposition during prolonged exposure. Extremely weak emission in the 600-800 nm region is attributed to the low chromophore concentration in the multilayer films. These results contrast sharply with those of spin-coated polymer thin films and represent an encouraging first step toward the design of new multilayer architectures.

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The adsorption of antifreeze glycoprotein-fraction 8 (AFGP 8) was studied via a drop deposition method onto hydrophobic (HOPG) and hydrophilic (mica) surfaces. On HOPG, preferential adsorption occurred at the hydrophilic step edges with homogeneous nucleation on hydrophobic planes. Individual particle sizes are consistent with aggregates, and the uniform size of these particles suggests aggregation is a preadsorption event. The adsorption of AFGP 8 onto hydrophilic mica was also consistent with aggregates of individual molecules. Adsorption studies of other glycosylated and nonglycosylated proteins suggest that not only is the adsorption event onto different surfaces influenced by glycosylation but also secondary and tertiary protein structure may play a critical role.