Figure 1
From: Multifunctional Polymer-Based Graphene Foams with Buckled Structure and Negative Poisson’s Ratio
Synthesis and characterization of PG foams and A-PG foams with buckled geometry.
(a,b) Synthesis of polymer-based graphene (PG, b) foams using polyurethane (PU, a) foams as a three-dimensional scaffold template. (c) Mechanically manufacturing process caused triaxially buckled microstructural topology in A-PG foams. From top to bottom: schematic for microstructures, corresponding digital picture of cubic foams and SEM view of their cross-section (scale bars: 300 μm). (d) TEM image of graphene stripped from PG foams through dissolving the polymer skeletons. (e) Photographs of ignition processes of as-prepared foams in air. Compared to the parent PU and PG foams, A-PG foams hold most of microscopic framework and show much longer burn time without visible smoke during ignition, implying potential application in fire retardancy of graphene coating. Scale bars in the red (PG foam) and blue (A-PG foam) colored SEM view of burned foams is 100 μm. (f) Images showing the contact angle of a water drop: 127° on A-PG foams, 112° on PG foams and 84° on parent PU foams. (g) Photographs of tension process of A-PG foam indicate its excellent flexibility and negative Poisson’s ratio effect.
