communications www.MaterialsViews.com 4298 www.small-journal.com © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Bioinspired, Ultrastrong, Highly Biocompatible, and Bioactive Natural Polymer/Graphene Oxide Nanocomposite Films Wen-Kun Zhu, Huai-Ping Cong, Hong-Bin Yao, Li-Bo Mao, Abdullah M. Asiri, Khalid A. Alamry, Hadi M. Marwani, and Shu-Hong Yu* highly intense and ultratough composites have been reported by adopting diverse self-assembly techniques such as layer- by-layer (LBL) assembly, vacuum filtration-assisted assembly, freeze-drying assembly, interface-assisted self-assembly and Langmuir–Blodgett (LB) assembly. [6–10] In these cases, 2D inorganic assembly units including glass flake, alumina flake, graphene oxide (GO), layered double hydroxides (LDH), nanoclay and flattened double-walled carbon nanotube, etc., serve as “bricks”, while polymers act as “mortar”. [2,11] Notably, GO nanosheet is an ideal kind of 2D inorganic building blocks for assembly of nacre-like materials, owing to its unique physicochemical properties and easily-accessed advantage. [12–14] Among GO-based composites, nacre-like GO-polymer materials have attracted great interests due to the endowed excellent mechanical performances. [15–17] Till now, a large number of reports have been focused on the assembly of GO with the synthesized polymers, rather than natural polymers. However, in consideration of the growing exhaustion of fossil resources, such as petroleum and coal in polymer industries, and the resulted wastes from the nonde- gradable organic polymer materials, it is pressing to reduce the production of traditional petroleum-based material and develop the novel composites with natural polymers in chem- istry and materials science. [18–21] As a renewable natural polymer, konjac glucomannan (KGM) exhibits excellent biocompatible and biodegradable properties. [22,23] Meanwhile, it possesses great advantages of gelling, film-forming, antibacterial action, and low calorific value, enabling its broad applications in chemical, biolog- ical, food, and medical industries. [24–28] Furthermore, KGM is a kind of promising components for the construction of strong material with GO through the hydrogen-bond interac- tion, etc., due to abundant of hydroxyl groups in its polymer chains. In the present study, we report the preparation of KGM– GO nanocomposite films with nearly B&M hierarchical struc- ture via a simple solution casting method. Compared with pure KGM film, the Young’s modulus and tensile strength of KGM–GO nanocomposite film with 7.5% GO are increased by 92.6% and 151.6%, respectively. It is worth to note that the ultimate tensile strength of such KGM–GO nanocom- posite film can reach up to 183.3 MPa, exceeding many other biopolymer/GO films. Furthermore, the as-prepared DOI: 10.1002/smll.201500486 Nanocomposites Dr. W.-K. Zhu, Dr. H.-B. Yao, Dr. L.-B. Mao, Prof. S.-H. Yu Division of Nanomaterials and Chemistry Hefei National Laboratory for Physical Sciences at Microscale Collaborative Innovation Center of Suzhou Nano Science and Technology Department of Chemistry The National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei, Anhui 230026, P. R. China E-mail: shyu@ustc.edu.cn Dr. W.-K. Zhu State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials Southwest University of Science and Technology Mianyang, Sichuan 621000, P. R. China Prof. H.-P. Cong School of Chemistry and Chemical Engineering Hefei University of Technology Hefei, Anhui 230039, P. R. China Prof. A. M. Asiri, Dr. K. A. Alamry, Dr. H. M. Marwani Center of Excellence for Advanced Materials Research Chemistry Department Faculty of Science King Abdulaziz University Jeddah 21589, Saudi Arabia With the fast development of science and technology, one of the major scientific challenges in the field of materials science is to create novel, multifunctional materials with advanced performance, and therefore, build strong foundations for diverse fantastic fields. [1] In the process of evolution, nature has point out intrinsic laws to produce lightweight, strong, and hierarchical materials with exceptional properties and functionalities. [2,3] Biological materials, such as tooth, bone, and nacre, are complex, hierarchical, and heterogeneous nanocomposites providing superior mechanical properties and biocompatibility. [4,5] Thus, design and fabrication of bio- inspired natural/biological materials with controllable archi- tecture, especially with outstanding mechanical properties, is a viable approach for developing advanced functionalities. Inspired by the unique multiscale and multilevel “brick- and-mortar”(B&M) structure in nacre, a series of bio-inspired small 2015, 11, No. 34, 4298–4302