Background:

Hybrid organic-inorganic nanocomposites of polymers and clay platelets represent a type of advanced material with promising applications in biosensing and catalysis, as well as in the fuel cell and pharmaceutical industries, including applications involving the controlled release of drugs. These materials also have superior gas barrier functions and are useful as fire retardants. Clay is an inexpensive material that is chemically and thermally stable. Clay nanosheets interact with synthetic polymers, organic cations, amino acids and proteins. Because of the high aspect ratio and high surface-to-volume ratios of clay nanosheets, the addition of small amounts of a clay such as montmorillonite to polymer materials significantly improves the mechanical and thermal properties of the resulting nanocomposites. Positively-charged polymers and/or cationic surfactants can adsorb at the silicate surfaces of the clay via electrostatic interactions with negative charges at the clay basal plane. Moreover, organo-modified clays are broadly used in the preparation of nanocomposites, allowing introduction of specific functionalities into the nanocomposite materials via an appropriate selection of molecules adsorbed to the clay. Recently, attention has been attracted by advanced functional stimuli-responsive materials constructed from organic and inorganic components, in response to a growing demand to deliver certain molecules at specific conditions when and where their activities are desired.

Summary:

The present invention includes films for the retention and controlled release of organic and inorganic molecules, which consist essentially of platelets of phyllosilicate clay and an organic polyanion. These films are layered films including alternating layers of phyllosilicate clays and organic polyanions by layer-by-layer (lbl) method and they carry organic or inorganic molecules absorbed within it. When the film is immersed in a solution of organic or inorganic molecules for a sufficient time, the molecules get absorbed into the film. The present invention includes an article with a film consisting essentially of a phyllosilicate clay and an organic polyanion adhering to it.

Benefits:

- Inexpensive compared to existing technologies (usage of clay)

Applications:

- Coating of materials that need release based on change in environmental conditions.

Full Patent: Clay-Containing Thin Coatings As Carriers Of Small Molecules