Polymer-Based Black Phosphorus (bP) Hybrid Materials by in Situ Radical Polymerization: An Effective Tool To Exfoliate bP and Stabilize bP Nanoflakes

Abstract

Black phosphorus (bP) has been recently investigated for next generation nanoelectronic multifunctional devices. However, the intrinsic instability of exfoliated bP (the bP nanoflakes) toward 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 (bPn) 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 dimethyl sulfoxide, DMSO) with poly(methyl methacrylate) (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 the bPn is 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. The feasibility of this approach, capable of efficiently exfoliating bP while protecting the bPn, has been then verified by using different vinyl monomers (styrene and N-vinylpyrrolidone), thus obtaining hybrids where the nanoflakes are embedded in polymer matrices with a variety of intriguing thermal, mechanical, and solubility characteristics.

Ultrafast Sodium/Potassium‐Ion Intercalation into Hierarchically Porous Thin Carbon Shells

“…The Raman spectra also exhibited a slightly redshift after cycling with Na + /K + ions, which further points toward the expansion of carbon lattice from the 0.375 to the 0.4 nm interlayer spacing. This is consistent with the post‐electrochemical HRTEM analysis . A slight Raman shift was observed in PVPC‐based electrode materials, which is also consistent with the HRTEM analysis and indicates minimal change in lattice spacing upon reversible cycling.…”

Exfoliation of 2D Materials for Energy and Environmental Applications

“…Passaglia et al. further exploited covalent modification to fabricate nanocomposites through in situ radical polymerization after thermal initiation of AIBN . It is considered that not only thermolysis of the radical precursor but also other activation or initiation procedures such as photolysis, electrolysis, or redox radical initiation could further develop radical‐mediated covalent functionalization…”

2D Elemental Nanomaterials Beyond Graphene

“…The phosphonium ylide of phosphorene formed by benzyl group can react with aldehydes to produce alkenes such as stilbene through the Wittig reaction. Encapsulation of BP with ambient stable organic polymers such as poly(vinyl alcohol) (PVA), poly (methyl methacrylate) (PMMA), and poly[(1,4‐diethynylbenzene)‐alt‐9,9‐bis(4‐diphenylaminophenyl)fluorene](PDDF), has been a quite successful strategy to stabilize phosphorene. Other strategies such as non‐covalent functionalization, and doping have also been employed …”