If the name sounds familiar, it's because fluorocarbon covers a broad family of compounds, including organics comprised of fluorine, chlorine and carbon, along with synthetics made from hydrocarbons—and has been used in everything from Teflon to Freon.
Many anglers believe that fluorocarbon is a low-stretch line, and credit its sensitivity to this factor. But it actually stretches more than nylon mono. The difference is, it takes a greater force to get fluoro stretching in the first place. As a result, fluoro makes a fine choice for situations where controlled stretch is helpful, whether as a mainline or a leader in conjunction with low-stretch superline. Paired with its higher density and direct contact due to its sinking ability this line is incredibly sensitive.
In the fishing world, it's associated with polyvinylidene difluoride (PVDF for short). It's extruded in a single strand similar to nylon monofilament. But because fluorocarbon's molecules are more tightly packed, the line is denser and noticeably heavier by size. It also differs from mono in visibility, stretch and durability—all of which affect how it performs in the water.
