First MALDI-TOF mass spectrometry of vinylidene fluoride telomers endowed with low defect chaining

The radical telomerization of vinylidene fluoride (or 1,1-difluoroethylene, VDF) with iodotrifluoromethane initiated by tert-butyl peroxypivalate is presented. The VDF telomers obtained were characterized by H-1 and F-19 NMR spectroscopy and by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI TOF MS) that revealed low polydispersity indexes showing a pseudo-living character of this reaction regarded as an iodine transfer polymerization process. CF3 and CF2I end groups appear as suitable labels in the F-19 NMR spectra to assess the number-average molar masses of these VDF telomers ((M) over bar (n)). Both these techniques showed a good agreement in terms of degree of telomerization, and the first examples of MALDI-TOF mass spectra of fluorotelomers are presented. Interestingly, all telomers obtained exhibit the structure CF2CH2CF2(VDF)(n)I, showing that (i) the trifluoromethyl radical preferentially attacked the methylene site of VDF with a high regioselectivity; (ii) the only transfer reaction arose from that to the CF3I and not from the monomer, the initiator, the solvent, or the polymer; and (iii) a very low defect of VDF chaining (0.73% regarded as the lowest one noted in the literature) was observed.