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We describe the synthesis and associative behavior in water of a strictly alternating comblike amphiphilic polymer based on poly(ethylene glycol) (PEG). The polymer has a strictly alternating sequence of PEG blocks (M w = 8000) of low polydispersity and hydrophobic 18 carbon-atom alkyl pendent chains. Three copolymers with M w = 28 000, 68 000, and 113 000 were prepared. The associative behavior of the polymer of molecular weight 28 000 (on average about 3 PEG-C18 sequences per chain) in water was studied by static and dynamic light scattering, spectrofluorimetry, and viscosity measurements. The behavior resembles that of hydrophobically end capped (i.e., telechelic) PEO. Flowerlike micelles, each containing approximately 14 hydrophobes, are formed by the association of about four to five polymer chains.

A one-step, fast, and potential low cost process has been developed to fabricate silicalike glass nanostructures by combining sol-gel chemistry and thermal nanoimprint. An inorganic-organic sol-gel thin film is patterned at low pressure and temperature with flexible stamps. Various geometries are achieved with a patterning resolution of about 150nm and pattern aspect ratio higher than 4. To obtain pure silica structures a thermal annealing at high temperatures is required. During this step most of the structures collapse due to fluidization of the sol-gel material. It is shown that if a suitable condensation level is obtained during imprinting, the nanostructures are thermally stable.

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We used an epoxysilane/aminosilane coating deposited from an aqueous solution to strengthen flat glass. We studied film formation, interfacial and mechanical properties of the film. The film is highly cross-linked with a 6 GPa YoungÕs modulus and good adhesion. Our results suggest that crack face bridging accounts for most of the 75% reinforcement in this system.

We describe the associative behavior of a strictly alternating comblike amphiphilic polymer in aqueous surfactant (sodium dodecyl sulfate (SDS)) solutions. The polymer contains normal stearyl pendent hydrophobic groups separated by poly(ethylene glycol) (PEG) of molecular weight 8000. The average number of hydrophobes per chain is 9. In the dilute regime in the presence of very low amount of SDS, the polymer associates mainly in flowerlike micelles very similar to those formed by a sample of similar structure but a lower degree of polymerization (on average, two to three hydrophobes per chain). Further addition of SDS leads to the formation of mixed micelles of decreasing N R (number of hydrophobes from the polymer per micelle). Flowerlike conformation is preserved until a SDS concentration which coincides with the critical aggregation concentration (cac) of SDS in the presence of poly(ethylene oxide) (PEO), after which the structure is disrupted. In the absence of SDS, below the polymer overlapping concentration c*, bridging between micelles leads to phase separation between a highly viscous phase rich in polymer (network of interconnected flowerlike micelles) and a phase of very low viscosity. In the semidilute regime, the viscosity against SDS concentration exhibits a maximum, a classical result for hydrophobically modified polymers interacting with surfactant micelles. The covalent linkage between the PEG−C18 sequences belonging to the same polymer chain that bridges multiple micelles is responsible for the enhanced viscosity as compared to the telechelic PEO. Rheological data show evidence of the transition from a network of interconnected flowerlike micelles to an extended uniformly connected network upon addition of SDS.

In the context of glass fiber manufacture, the onset of lubrication by a C(18) double-chained cationic surfactant has been investigated at high normal contact pressures. Comparison with adsorption kinetics demonstrates that lubrication is not directly connected to the surfactant surface excess but originates from the transition to a defect-free bilayer that generates limited dissipation. The impact of ionic strength and shear rate has also been studied.