From Fragility to Flexibility: Construction of Hydrogel Bridges toward a Flexible Multifunctional Free‐Standing CaCO₃ Film

Abstract

Free-standing CaCO 3 materials are an important member in biological systems because of their existence in many natural organisms such as nacre, shell, and crustacean cuticle. However, toughness of those artificial mineral films is sacrificed once their inorganic content is up to 90%, thus freestanding characteristics have seldom been achieved for CaCO 3 films, let alone their real applications. Herein a fast and simple method for constructing hydrogel "bridges" for CaCO 3 microparticles is presented, developing highly flexible free-standing CaCO 3 films with only 5% organic content. Such integrated films have underwater superoleophobicity and self-cleaning function, which guarantee their repeated application in oil/water separation. Furthermore, heavy metal ions can be efficiently removed by simple filtration with the films. Because of the self-similar structure, the films are able to resist mechanical abrasion without losing the anti-wetting property and separation efficiency. The free-standing CaCO 3 films are put forward for the first time to practical application, demonstrating the strategy can bring a brilliant prospect to artificial biomineral materials.

Hierarchically porous membranes for lithium rechargeable batteries: Recent progress and opportunities

“…Doped ZnO seed‐nanoparticle polymeric membranes were prepared by phase separation, which enabled a pore‐specific in situ growth of small (<5 μm in diameter) ZIF‐8 islands, as shown in Figure 8G,H 98 . Wang et al suggested a simple method for constructing hydrogel “bridges” for freestanding CaCO 3 films, 99 Figure 8J shows CaCO 3 microparticles connected to a silk‐like “adhesive,” acting as a spider web. Hydrogel bridges dragged the rigid CaCO 3 particles together, enhanced the flexibility of multifunctional membranes, and provided abundant freedom space among the inorganic particles.…”

Nacre-inspired Hard and Tough Materials

“…Using this strategy, free-standing two dimensional (2D) sheets have been produced by infiltrating a thin layer of alginate, crosslinked with Ca 2+ , with a carbonate source such as Na 2 CO 3 to form CaCO 3 particles inside the alginate matrix. [34] Similarly, three dimensional (3D) composites have been produced from carboxyfunctionalized cellulose nanofibrils that are assembled into 3D hydrogels [35] or from poly(2-hydroxyl methacrylate) (PHEMA) hydrogels. [36] These composites are tough: They reach yield stresses of 200 MPa [35] while they can be strained by up to 8%.…”

Amylopectin Regulated Mineralization of Calcium Carbonate and Its Application in Removing of Pb(II)

“…Researchers' inspiration for biomineralization comes from the pearl layer, where they found that biominerals with well-defined layered structure are made up of 95 wt% CaCO 3 and 5 wt% organic compounds. [1][2][3] In the process of biomineralization, the interaction between a series of biological macromolecules (such as proteins, [4,5] chitins, [6] polysaccharides, [7][8][9] and inorganic substances promote the deposition of inorganic crystals in organisms and further form organic-inorganic composite materials, it DOI: 10.1002/crat.202100012 also allows organisms to possess complex properties and polytropic forms. [10] CaCO 3 is a kind of sparingly soluble salt, which is utilized by nature to fabricate exceptionally stable and tough materials.…”