Polymer covered gold colloid

Metal colloids have been known for years—red stained glass is gold in colloidal form in glass, for example. Aqueous colloids are preparations that contain metal particles of 20-1000 A diameter in which the metal does not precipitate because the surface of the particles is covered in a way that protects them from agglomeration the hydrophilic polymer polyvinylalcohol (PVA) is an effective stabilizing agent. In a typical preparation, an aqueous solution of a metal salt is reduced in the presence of PVA. Small metal clusters have a precisely defined nuclearity (number of metals) and structure, but colloid... 

Atomic Force Microscopy (AFM) and Transmuision Electron Microscopy (TEM). Measurements were carried out with a MultiMode AFM (Digit Instruments). The tapping mode was applied. The polymer was dissolved in 2,2,3,3-tetrafluoro-l-propanol or THF and a film was formed by slow evaporation of the solvent at ambient temperature. The samples for TEM were dissolved in water and in some cases colloidal gold was added. The solutions were cast onto copper grids covered with a carbon fihn. A Zeiss-CEM902 was used with an acceleration voltage of 80 kV. 

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