Article Cite This: Acc. Chem. Res. XXXX, XXX, XXX−XXX
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Cladophora Cellulose: Unique Biopolymer Nanofibrils for Emerging Energy, Environmental, and Life Science Applications Shengyang Zhou,† Leif Nyholm,‡ Maria Strømme,*,† and Zhaohui Wang*,‡ †
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Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, Uppsala 751 21, Sweden ‡ Department of Chemistry-Ångström, Uppsala University, Box 538, Uppsala 751 21, Sweden CONSPECTUS: Because of its natural abundance, hierarchical fibrous structure, mechanical flexibility, potential for chemical modification, biocompatibility, renewability, and abundance, cellulose is one of the most promising green materials for a bio-based future and sustainable economy. Cellulose derived from wood or bacteria has dominated the industrial cellulose market and has been developed to produce a number of advanced materials for applications in energy storage, environmental, and biotechnology areas. However, Cladophora cellulose (CC) extracted from green algae has unprecedented advantages over those celluloses because of its high crystallinity (>95%), low moisture adsorption capacity, excellent solution processability, high porosity in the mesoporous range, and associated high specific surface area. The unique physical and chemical properties of CC can add new features to and enhance the performance of nanocellulose-based materials, and these attributes have attracted a great deal of research interest over the past decade. This Account summarizes our recent research on the preparation, characterization, functionalization, and versatile applications of CC. Our aim is to provide a comprehensive overview of the uniqueness of CC with respect to material structure, properties, and emerging applications. We discuss the potential of CC in energy storage, environmental science, and life science, with emphasis on applications in which its properties are superior to those of other nanocellulose forms. Specifically, we discuss the production of the first-ever paper battery based on CC. This battery has initiated a rising interest in the development of sustainable paper-based energy storage devices, where cellulose is used as a combined building block and binder for paper electrodes of various types in combination with carbon, conducting polymers, and other electroactive materials. High-activemass and high-mass-loading paper electrodes can be made in which the CC acts as a high-surface-area and porous substrate while a thin layer of electroactive material is coated on individual nanofibrils. We have shown that CC membranes can be used directly as battery separators because of their low moisture content, high mesoporosity, high thermal stability, and good electrolyte wettability. The safety, stability, and capacity of lithium-ion batteries can be enhanced simply by using CC-based separators. Moreover, the high chemical modifiability and adjustable porosity of dried CC papers allow them to be used as advanced membranes for environmental science (water and air purification, pollutant adsorption) and life science (virus isolation, protein recovery, hemodialysis, DNA extraction, bioactive substrates). Finally, we outline some concluding perspectives on the challenges and future directions of CC research with the aim to open up yet unexplored fields of use for this interesting material.
1. INTRODUCTION
ismsin particular cellulose from wood (WC) and from Acetobacter xylinum bacteria (BC)have been extensively studied.2,3 In 2002, we found that cellulose derived from green algae (Cladophora) is a unique nanocellulose with an unprecedented combination of very high crystallinity and large fiber aspect ratio.5 Cladophora cellulose (CC) is easy to extract and has outstanding solution processability, tunable mesoporosity, high surface area, high chemical stability, low moisture absorption, robust and flexible mechanical properties, and diversified surface modifiability. These characteristics can be used to form new features and enhance its performance,
As the most abundant natural biopolymer on earth, cellulose is one of the earliest and most continuously used materials employed by humans.1,2 The traditional applications of cellulose have been widely extended with the discovery of nanocellulose; its advantages, including the nanofibrillar structure, mechanical flexibility, and surface functionality, have already been demonstrated in many emerging interdisciplinary fields. The nanofibrils can be assembled into strong fibers, transparent papers, or light aerogels, which have great potential in applications requiring high-performance structural materials, flexible transparent substrates for electronics or displays, multifunctional aerogels for adsorption, insulation, or sensors.3,4 Nanocellulose from land plants and microorgan© XXXX American Chemical Society
Received: April 28, 2019
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DOI: 10.1021/acs.accounts.9b00215 Acc. Chem. Res. XXXX, XXX, XXX−XXX
Article
Accounts of Chemical Research
Figure 1. Overview of three widely studied cellulose nanofibers with the same molecular chain structure but different morphologies, showing the range of scales for the different growth environments. Reproduced with permission from refs 2, 3, 6, and 17. Copyright 2011 Wiley-VCH, 2015 American Chemical Society, 2011 Wiley-VCH, and 2009 American Chemical Society, respectively.
Table 1. Comparison of Some of the Structural Parameters of Cellulose Nanofibrils from Wood, Bacteria, and Cladophora Algae6−12 material
degree of crystallinity (%)
size of crystalline region (nm)
crystal form
length (nm)
diameter (nm)
aspect ratio
surface area by N2 (m2/g)
surface area by H2O (m2/g)
volume of micro- and mesopores (cm3/g)
WC BC CC
∼50−80 ∼84−89 >95
∼100 ∼300 ∼600
Iβ Iα Iα
∼200 ∼900 ∼4000
3−5 10−20 15−30
14 47 160
0.48−0.96 −a 95
117−204 −a 52.8
