A Hydrogel‐Film Casting to Fabricate Platelet‐Reinforced Polymer Composite Films Exhibiting Superior Mechanical Properties

Abstract

The fabrication of mechanically superior polymer composite films with controllable shapes on various scales is difficult. Despite recent research on polymer composites consisting of organic matrices and inorganic materials with layered structures, these films suffer from complex preparations and limited mechanical properties that do not have even integration of high strength, stiffness, and toughness. Herein, a hydrogel-film casting approach to achieve fabrication of simultaneously strong, stiff, and tough polymer composite films with well-defined microstructure, inspired from a layer-by-layer structure of nacre is reported. Ca -crosslinked alginate hydrogels incorporated with platelet-like alumina particles are dried to form composite films composed of horizontally aligned alumina platelets and alginate matrix with uniformly layered microstructure. Alumina platelets are evenly distributed parallel without precipitations and contribute to synergistic enhancements of strength, stiffness and toughness in the resultant film. Consequentially, Ca -crosslinked alginate/alumina (Ca -Alg/Alu) films show exceptional tensile strength (267 MPa), modulus (17.9 GPa), and toughness (3.60 MJ m ). Furthermore, the hydrogel-film casting allows facile preparation of polymer composite films with controllable shapes and various scales. The results suggest an alternative approach to design and prepare polymer composites with the layer-by-layer structure for superior mechanical properties.

Bioinspired Design and Fabrication of Polymer Composite Films Consisting of a Strong and Stiff Organic Matrix and Microsized Inorganic Platelets

“…When we compared the Ca 2+ –Alg, Ca 2+ Alg/Alu, and Ca 2+ –Alg/Alu–PVP films under RH 15 and 30%, the incorporation of bare Alu platelets in the film contributed to less improved mechanical properties at RH 30% than at RH 15%. At the highly dry condition (RH 15%), the Ca 2+ –Alg film was basically brittle and exhibited only elastic deformation, whereas the Ca 2+ –Alg/Alu composite film was ruptured with a slight plastic deformation under the platelet pull-out mode, of which the phenomenon is the same as that of our previous report . At the moderately dry condition (RH 30%), the water molelcules existing in the film softened the polymer matrix and allowed for a higher plastic deformation even in the Ca 2+ –Alg film.…”

“…We herein present inorganic microplatelet-reinforced, strong, stiff, and tough polymer composite films based on the rational design of each component and the control of interfacial interactions between the organic and inorganic phases. The composite film consists of strong and stiff organic matrices and horizontally aligned two-dimensional (2D) alumina (Alu) microplatelets in a uniformly layered microstructure that was achieved by an alternative method, that is, hydrogel film casting suggested in the recent work by our group . An ionic cross-linked alginate (Alg) hydrogel maintains a three-dimensional structure and allows for a uniform distribution of inorganic microplatelets without precipitation to produce composite films with desirable shapes, sizes, and thicknesses.…”

Bioproduced Polymers Self-Assemble with Graphene Oxide into Nanocomposite Films with Enhanced Mechanical Performance

“…The abundant oxygen-containing functional groups on both GO and PGA provided the basis for the formation of hydrogen bonds, which increased the tensile strength of the films. Finally, Ca 2+ is reported to have a strong ability to chelate with anionic polymers 58 and was thus likely able to interlink the PGA polymer chains within the GO nanosheets via complexing with these oxygen-containing functional groups. As a result, we conclude that our materials formed a cross-linked structure with strong intercalations between PGA, GO, and Ca 2+ ions (Figure 6b).…”

Nacreous aramid-mica bulk materials with excellent mechanical properties and environmental stability

“…Then, the expected nacreous ANFs-Mica film could be obtained by drying this hydrogel via evaporating its containing DIW ( Figures S3 E and S3F). It was supposed that mica microplatelets embedded in the hydrogel were gradually organized in parallel to each other along the surface direction during this evaporation process ( Ji et al., 2018 ), resulting in the typical nacreous “bricks-and-mortar” microstructure ( Figure 1 C). These films were further cut with equal size, modified with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and laminated together with epoxy resin as the interfacial adhesive among the films, forming the expected nacreous ANFs-Mica bulk with desired size ( Figure 1 D).…”

“…After assembling the two kinds of nanoscale building blocks into nacreous ANFs-Mica films ( Figure S7 ), their intrinsic merits were supposed to be successfully integrated together and transferred to the ANFs-Mica films. The cross-sectional morphology of the ANFs-Mica films shows typical nacreous layered structure ( Figures 2 A and S8 ), which was formed via evaporation-induced self-assembly of the building blocks during the drying process of the ANFs-Mica hydrogels ( Ji et al., 2018 ). Moreover, the ANFs-Mica film (40 wt.%) with different thicknesses could be easily fabricated by adjusting the thickness of the deposited gels ( Figure S9 ).…”