Folding Large Graphene‐on‐Polymer Films Yields Laminated Composites with Enhanced Mechanical Performance. Issue 35 (11th July 2018) - Wang, Bin
Abstract: A folding technique is reported to incorporate large‐area monolayer graphene films in polymer composites for mechanical reinforcement. Compared with the classic stacking method, the folding strategy results in further stiffening, strengthening, and toughening of the composite. By using a water–air‐interface‐facilitated procedure, an A5‐size 400 nm thin polycarbonate (PC) film is folded in half 10 times to a ≈0.4 mm thick material (1024 layers). A large PC/graphene film is also folded by the same process, resulting in a composite with graphene distributed uniformly. A three‐point bending test is performed to study the mechanical performance of the composites. With a low volume fraction of graphene (0.085%), the Young's modulus, strength, and toughness modulus are enhanced in the folded composite by an average of 73.5%, 73.2%, and 59.1%, respectively, versus the pristine stacked polymer films, or 40.2%, 38.5%, and 37.3% versus the folded polymer film, proving a remarkable mechanical reinforcement from the combined folding and reinforcement of graphene. These results are rationalized with combined theoretical and computational analyses, which also allow the synergistic behavior between the reinforcement and folding to be quantified. The folding approach could be extended/applied to other 2D nanomaterials to design and make macroscale laminated composites with enhanced mechanical properties. Abstract : A large‐area monolayer graphene film is incorporated in polymer by a folding method, obtaining a mechanically reinforced laminated composite with 1024 stacked layers (10 folds). The folds result in additional stiffening, strengthening, and toughening of the composite with respect to the simply stacked counterpart: synergistic interaction of graphene and folding leads to the exploitation of the ideal properties of the graphene reinforcement.