This paper provides an overview of recent progress made in the area of cellulose nanofibre-based nanocomposites. An introduction into the methods used to isolate cellulose nanofibres (nanowhiskers, nanofibrils) is given, with details of their structure. Following this, the article is split into sections dealing with processing and characterisation of cellulose nanocomposites and new developments in the area, with particular emphasis on applications. The types of cellulose nanofibres covered are those extracted from plants by acid hydrolysis (nanowhiskers), mechanical treatment and those that occur naturally (tunicate nanowhiskers) or under culturing conditions (bacterial cellulose nanofibrils). Research highlighted in the article are the use of cellulose nanowhiskers for shape memory nanocomposites, analysis of the interfacial properties of cellulose nanowhisker and nanofibrilbased composites using Raman spectroscopy, switchable interfaces that mimic sea cucumbers, polymerisation from the surface of cellulose nanowhiskers by atom transfer radical polymerisation and ring opening polymerisation,

Glass has well-suited low thermal expansion for use in electronic devices, but it is fragile, and the search for a stronger, more flexible optically clear medium has gone on for many years. Plastics have been widely studied; however, most of them have large coefficients of thermal expansion (CTE, approx. 50 ppm K À1 ), and foldable plastics in particular exhibit extremely large CTEs, in excess of 200 ppm K À1. Further, the functional materials deposited on plastic substrates are prone to be damaged by the temperatures involved in the assembly and mounting processes due to the mismatch between CTEs from different materials. This article reports on what might be best described as optically transparent paper. It is a foldable nanofiber material with low thermal expansion (CTE <8.5 ppm K À1 ) prepared using 15 nm cellulose nanofibers with the same chemical constituents as conventional paper and a production process also similar to that of conventional paper. The only difference is in the fiber width and the size of the interstitial cavities (Fig. 1). The foldable, low-CTE, and optically transparent nanofiber paper is the perfect candidate for substrates for continuous roll-to-roll processing in the future production of electronic devices, such as flexible displays, solar cells, e-papers, and a myriad of new flexible circuit technologies, and could replace the costly conventional batch processes based on glass substrates currently used. [1][2][3][4][5] We project that it will also replace conventional paper as an advanced information medium, which can still be produced using traditional paper-making equipment that is used in production today.Cellulose nanofibers are the main component of plant and wood pulp fibers. These tiny elements with diameters of 15-20 nm are composed of bundles of cellulose microfibrils smaller than 4 nm in width, which, in turn, are composed of long cellulose molecules laterally stabilized by hydrogen bonds forming highly crystalline domains. As such, cellulose nanofibers have a CTE of 0.1 ppm K À1 , [6] which is as low as that of quartz glass, and an estimated strength of 2-3 GPa, [7] rendering it five times stronger than mild steel. The nanofibers also exhibit good heat-transfer properties comparable to glass.[8] Another significant property of the nanofibers is that light scattering can be suppressed. [9,10] If the cellulose nanofibers are densely packed, and the interstices between the fibers are small enough to avoid light scattering, the cellulosic material becomes transparent while maintaining the high performance of the material described before.To obtain the nanofibers from plants and wood fibers, it is necessary to disassemble the fibers' original structure. The cell walls of the fibers are composed of several thin layers, in which the cellulose nanofibers are oriented in various directions and embedded in matrix substances. In order to extract uniform nanofibers from this complex structure, wood flour was used as a starting material. The wood flour was ground in a water-swollen cond...

sist was spin-coated on the surface of PEG-modified silicon wafers. After exposure to UV light under a photomask, the wafers were immersed in developing solution and then etched via wet etching. The remaining photoresist was removed using acetone.Self-Assembly of Protein/Silica Nanoparticles in Microwells: The etched silicon wafer was rinsed three times with deionized water, followed by drying of the wafer with dry air. The wafer was immersed in a freshly prepared 1 mg mL ±1 solution of protein/silica nanoparticles for 6 h at room temperature. Then, the wafer was rinsed carefully in deionized water and sonicated in deionized water for 5 min to remove free nanoparticles.Atomic Force Microscopy (AFM) and Fluorescence Microscopy Measurements: The tapping mode AFM images were taken using a Digital Instruments Nanoscope IIIa DIMM AFM atomic microscope operating at room temperature with an image resolution of 256 pixels 256 pixels at a scan speed of 0.7±1.2 Hz in air. Light and fluorescence photographs were obtained using an Axiostar plus fluorescent microscope with a color charge-coupled device (CCD) camera and image-acquisition system. Mechanical reinforcement of optically functional materials is of significant interest to various industries due to the rapid expansion of related devices, such as displays. Nanocomposite materials with components less than one-tenth of a wavelength in size are free from scattering, making them acceptable for a variety of optical applications. [1,2] Since fibers could provide the desired mechanical reinforcement of optically functional materials, reinforcement using nanofibers of electrospun nylon-4,6 has been studied. An optically transparent composite was obtained at a fiber content of 3.9 %, [3] but an inevitable difficulty remains in the way of obtaining highfiber-volume composites without losing transparency. Herein we report the first example of a transparent composite reinforced with bacterial nanofibers. The composite is optically transparent at a fiber content as high as 70 %, with a low thermal-expansion coefficient (similar to that of silicon crystal) and a mechanical strength five times that of engineered plastics. These significant improvements in the thermal and mechanical characteristics of the composite are due to the web-like network of the semicrystalline extended chains of nanofibers, produced by the bacterium Acetobacter xylinum (Glucronobacter aceti). The nanofiber-network-reinforced polymer composite maintains its transparency. It is light, flexible, and easy to mould, thus making it an excellent candidate COMMUNICATIONS

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