Science: Alsifilm

The chemist was astonished. He had put his finger on a whitish deposit covering the inside of a glass vessel not much bigger than a thimble. He expected this substance to crumble at his touch. Instead, it came out intact, like a smooth, tough vellum paper. It stood on his desk, forming a model of the vessel which it had lined.

This happened not long ago in the chemical engineering laboratories of Massachusetts Institute of Technology, where Associate Professor Ernst Alfred Hauser and a blonde, slim young woman chemist who was his co-worker were investigating the properties and behavior of bentonite. Mined in Canada and the western U. S., bentonite is a kind of clay which has the property of swelling when it is wetted, absorbing up to ten times its own volume of water. It is used for foundry molding, in tooth pastes, face powder and facial mud packs.

In the course of his experiments, Dr. Hauser made a gelatinous blob of wet bentonite which he dried out ‘in order to ascertain the weight shrinkage. The paper-like lining which surprised him was then deposited. Under the microscope he saw that the minute clay particles had joined together in long chains which matted, making a tough, pliant membrane. This phenomenon, though familiar in organic substances, was not previously known to occur in minerals such as clay.* Dr. Hauser’s theory is that the bentonite clay particles are electrically charged, and so line up end to end in chains by polar attraction.

Last week Dr. Hauser’s bentonite film was billed as an excellent wrapping material for butter and other oily foods, as a good insulator for electric cables. It can be used like paper for printing and writing.

It is odorless, tasteless, impervious to fire and corrosion by acids. Because of its aluminum and silicon content, it has been named “Alsifilm.”

* Clay is a mixture of mineral debris (usually oxides of silicon and aluminum) which absorbs water molecules in chemical combination.