Several fluorescence techniques have been applied to characterize the aggregates of styrene-maleic anhydride copolymers (SMA). The formation of hydrophobic microdomains was confirmed by monitoring the I1/I3 ratios of pyrene dissolved in SMA solutions. Fluorescence quenching experiments indicate that protective quenching is occurring. The excimer-to-monomer ratio of di(1-pyrenylmethyl) ether and stoppedflow fluorescence measurements show that the interior of these SMA aggregates is extremely rigid, much more than that of typical surfactant micelles. Fluorescence anisotropy was applied to determine the hydrodynamic radius of these aggregates which was found to equal 1.7 ( 0.2 nm, in qualitative agreement with earlier measurements by small-angle X-ray scattering and small-angle neutron scattering. SMA aggregates have sizes similar to that of typical surfactant micelles, but their interior is frozen.

Two silicas obtained by precipitation have been compared using two 1H NMR techniques:  broad-line at 4 K with simulation of the spectra and MAS at room temperature. Previous 29Si high resolution NMR results have been used to interpret the spectra. Geminal silanols, single silanols, water molecules relatively strongly hydrogen-bonded to silanols, and water not interacting with OH groups have been characterized and quantified. Differences are found between the two precipitated silicas. Silanols, 70% of which can hydrogen-bond a water molecule, occupy all the surface of one of them. The other sample surface is not so crowded with silanols, and only 37% of them hydrogen-bond water molecules. Both geminal and single silanols hydrogen-bond water. Physisorbed water molecules not interacting with silanols can be equilibrated on both sample surfaces. Room temperature dehydration of the samples in vacuum is studied.

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