  Black phosphorus (bP) has been recently investigated for next generation
nanoelectronic multifunctional devices. However, the intrinsic instability of
exfoliated bP (the bP nanoflakes) towards both moisture and air has so far
overshadowed its practical implementation. In order to contribute to fill this
gap, we report here the preparation of new hybrid polymer-based materials where
bP nanoflakes exhibit a significantly improved stability. The new materials
have been prepared by different synthetic paths including: i) the mixing of
conventionally liquid-phase exfoliated bP (in DMSO) with PMMA solution; ii) the
direct exfoliation of bP in a polymeric solution; iii) the in situ radical
polymerization after exfoliating bP in the liquid monomer (methyl methacrylate,
MMA). This last methodology concerns the preparation of stable suspensions of
bPn-MMA by sonication-assisted liquid phase exfoliation (LPE) of bP in the
presence of MMA followed by radical polymerization. The hybrids characteristics
have been compared in order to evaluate the bP dispersion and the effectiveness
of the bPn interfacial interactions with polymer chains aimed at their
long-term environmental stabilization. The passivation of bPn results
particularly effective when the hybrid material is prepared by in situ
polymerization. By using this synthetic methodology, the nanoflakes, even if
with a gradient of dispersion (size of aggregates), preserve their chemical
structure from oxidation (as proved by both Raman and 31P-Solid State NMR
studies) and are particularly stable to air and UV light exposure.
