Sam Gilliam (b. 1933) is recognized as the first artist to introduce the idea of a painted canvas hanging without stretcher bars, c. 1965. He is most widely known for the large color-stained canvases he draped and suspended from the walls and ceilings during the late 1960s and early 1970s.
The above piece is "Light Depth," c. 1969, made with acrylic on canvas. But doesn't it look like silk? You can see it at The Corcoran and read more about it here.
Source: writing, Wikipedia; image of "Light Depth" from The Corcoran/www.corcoran.org.