Hydrogels from Amorphous Calcium Carbonate and Polyacrylic Acid: Bio-Inspired Materials for "Mineral Plastics"

• Published in: Angewandte Chemie International Edition Vol. 55; no. 39; pp. 11765 - 11769
• Main Authors: Sun, Shengtong, Mao, Li-Bo, Lei, Zhouyue, Yu, Shu-Hong, Cölfen, Helmut
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 19-09-2016; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Acrylic acid; Acrylics; amorphous calcium carbonate; Amorphous materials; bio-inspired synthesis; Biodegradability; Biodegradation; Bioplastics; Calcium; Calcium carbonate; Drying; Hydrogels; Mechanical properties; Nanoparticles; organic-inorganic hybrid composites; plasticity; Plastics; Polyacrylic acid; supramolecular hydrogels; Thermochromism; organic-inorganic hybrid composites; plasticity; amorphous calcium carbonate; supramolecular hydrogels; bio-inspired synthesis
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201602849

Given increasing environmental issues due to the large usage of non‐biodegradable plastics based on petroleum, new plastic materials, which are economic, environmentally friendly, and recyclable are in high demand. One feasible strategy is the bio‐inspired synthesis of mineral‐based hybrid materials. Herein we report a facile route for an amorphous CaCO3 (ACC)‐based hydrogel consisting of very small ACC nanoparticles physically cross‐linked by poly(acrylic acid). The hydrogel is shapeable, stretchable, and self‐healable. Upon drying, the hydrogel forms free‐standing, rigid, and transparent objects with remarkable mechanical performance. By swelling in water, the material can completely recover the initial hydrogel state. As a matrix, thermochromism can also be easily introduced. The present hybrid hydrogel may represent a new class of plastic materials, the “mineral plastics”.
Shapeable, stretchable, recyclable, (thermochromic) amorphous calcium carbonate‐based hybrid supramolecular hydrogels were synthesized, which can reversibly form macroscopic rigid transparent films upon drying. This plastic material may potentially replace conventional plastics in a move towards solving environmental issues.