In a 100-mL beaker, mix 10 mL of 1 M NaOH in 15 mL of H 2 0. Carefully pour the water solution down the side of the 250-mL beaker into the petroleum ether solution, without mixing the two. Using forceps, pick up the center of the film that forms at the interface of the two liquids. Slowly pull the nylon fiber from the beaker, and roll it up on a graduated cylinder that has a paper towel wrapped around it. A continuous thread of nylon is pulled from the center of the beaker.
Students can observe the formation of the fiber at the interface of the two solvents.