Keywords:Whisker, Organic dye, Silicone rubber
Toluene solution of fluorescent dye, i.e., dicyanomethylene (DCM), penetrates rapidly into silicone rubber. After the penetration, toluene evaporates from the silicone, and the residual DCM molecules occasionally create whiskers. The process of the whisker growth was observed by enclosing the solution in silicone; i.e., a spherical cavity (9 mm in diameter) was created in a silicone block by drying a swollen aqueous gel, and then the cavity was filled with the solution by using a syringe. Lots of whiskers (~2 mm in length) grew on the cavity surface after the penetration of the solution (1 day).