FMV 4031 Vinyl terminated trifluoropropylmethylsiloxane Gelest Silicone >> Vinyl functional Coatings Insoluble in water Vinyl terminated trifluoropropylmethylsiloxane. Used in coatings. Offers better hydrocarbon compatibility (greater solubility), higher refractive index, greater solvent resistance (lower hydrocarbon solubility) and lower refractive index than analogous dimethylsiloxane homopolymers. Vinyl terminated trifluoropropylmethylsiloxane. Used in coatings. Offers better hydrocarbon compatibility (greater solubility), higher refractive index, greater solvent resistance (lower hydrocarbon solubility) and lower refractive index than analogous dimethylsiloxane homopolymers.