Keywords: metal-organic frameworks • cellulose nanocrystals • aerogels • water purification • porous materialsThis work overcomes the longstanding challenge of processing metal-organic framework (MOF) powders into a convenient and tailorable form by entrapping them within a cellulose nanocrystal (CNC) aerogel. MOFs are a new class of porous materials, assembled from metal ions or ion clusters bridged by organic ligands. Since the pioneering work on MOF-5 reported by Yaghi and co-workers, [1] MOFs have received great attention due to their large surface area and porosity, high thermal stability, and tunable pore structure. MOFs have shown great potential in various applications including gas separation [2] and storage, [3] chemical sensing, [4] catalysis, [5] and so on. Designing and preparing new MOFs, [6] post-modification of existing MOFs, [7] and fabrication of MOFs into different structures [8] are currently of great interest.However, due to the crystalline nature of MOFs, they are most commonly found in powder form and their processability and handling remain a significant challenge. [9] Integrating MOFs onto or within various substrates to produce a shapeable, cost-efficient, and chemically inert product is one way to expand the potential applications of these functional materials.The deposition and growth of MOF particles on substrates has become a highly researched area but is severely constrained by the physical and chemical requirements of the substrate and gives materials with limited functionality. [10] Usually surface modifications are needed in Submitted to 2 order to increase the compatibility between MOFs and substrates, and while different methods to grow MOFs exist, including solvothermal, [11] secondary, [12] layer by layer growth, [13] and electrochemical deposition, [14] the substrates have to be stable during the process or restricted synthetic conditions must be employed. [15] Incorporation of MOF particles onto polymer or fiber substrates (of both synthetic [16] and natural origin [17] ), by blending, deposition or in situ growth, has been demonstrated. However, while these approaches overcome some of the disadvantages of preparing MOF-only materials or planar MOF films, most examples reported to date are either limited by low MOF loadings or reduced flexibility. [16b, 18] One alternative approach used to avoid processing or depositing MOFs is to produce metal organic framework gels (MOGs) which are high surface area MOF-like materials but they generally lack the ordered crystal lattice and desired physical properties of MOFs.[19]Nanocellulose shows great promise for use as a supporting substrate [20] or templating material [21] , especially in the form of cellulose aerogels and foams, because of its high strength, light weight, low cost, non-toxicity and its ability to be processed easily in water. [22] Cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose are the most common types of nanocellulose which are now being produced with con...

Air-conditioning" textiles with thermal-or moisture-managing functions are of high interest for not only improving human comfort but also reducing energy consumption. However, making the textile sensitive to the surrounding environment and exhibit adaptive thermal/moisture management still remains a great challenge. Herein, a double-sided synergetic Janus textile is developed, featuring reversible diode-like water transportation and adjustable thermal convection upon temperature change. The incorporated responsive polymer networks with inverse transitions on the opposite sides provide synergistic surface energy gradients and capillary gradients that generate drying and cooling effects (with 50% faster water evaporation and 1.2-2.3 °C cooler than with cotton fabric) in hot weather while offering thermal preservation (120 s longer needed to be cooled down and maximumly 3.3 °C warmer than with cotton fabric) in a cold environment. This method could provide ideas for the development of more adaptive textiles and clothing to address maximum personal comfort in demanding situations.

A major obstacle facing brain diseases such as Alzheimer's disease, multiple sclerosis, brain tumors, and strokes is the blood-brain barrier (BBB). The BBB prevents the passage of certain molecules and pathogens from the circulatory system into the brain. Therefore, it is nearly impossible for therapeutic drugs to target the diseased cells without the assistance of carriers. Nanotechnology is an area of growing public interest; nanocarriers, such as polymer-based, lipid-based, and inorganic-based nanoparticles can be engineered in different sizes, shapes, and surface charges, and they can be modified with functional groups to enhance their penetration and targeting capabilities. Hence, understanding the interaction between nanomaterials and the BBB is crucial. In this Review, the components and properties of the BBB are revisited and the types of nanocarriers that are most commonly used for brain drug delivery are discussed. The properties of the nanocarriers and the factors that affect drug delivery across the BBB are elaborated upon in this review. Additionally, the most recent developments of nanoformulations and nonconventional drug delivery strategies are highlighted. Finally, challenges and considerations for the development of brain targeting nanomedicines are discussed. The overall objective is to broaden the understanding of the design and to develop nanomedicines for the treatment of brain diseases.

This work reports a novel in situ growth approach for incorporating metal-organic framework (MOF) materials into an alginate substrate, which overcomes the challenges of processing MOF particles into specially shaped structures for real industrial applications. The MOF-alginate composites are prepared through the post-treatment of a metal ion cross-linked alginate hydrogel with a MOF ligand solution. MOF particles are well distributed and embedded in and on the surface of the composites. The macroscopic shape of the composite can be designed by controlling the shape of the corresponding hydrogel; thus MOF-alginate beads, fibers, and membranes are obtained. In addition, four different MOF-alginate composites, including HKUST-1-, ZIF-8-, MIL-100(Fe)-, and ZIF-67-alginate, were successfully prepared using different metal ion cross-linked alginate hydrogels. The mechanism of formation is revealed, and the composite is demonstrated to be an effective absorbent for water purification.

3D Hierarchical porous metal-organic framework (MOF) monoliths are prepared by using Pickering high internal phase emulsion (HIPE) template. Pickering HIPEs were stabilized solely by UiO-66 MOF particles with internal phase up to 90 % of the volume. The effects of internal phase type and volume, as well as MOF particle concentration on the stability of resulting Pickering HIPEs were investigated. Furthermore, by adding small amount of polyvinyl alcohol (PVA) as binder or polymerization in the continuous aqueous phase, followed by freeze-drying, two types of MOF-based 3D hierarchical porous monoliths with ultralow density (as low as 12 mg cm(-3) ) were successfully prepared. This Pickering HIPE template approach provides a facile and practical way for assembling of MOFs into complex structures.

Highly sensitive pressure sensors are usually made from soft materials that allow large deformations to be obtained when very small pressures are applied. Unfortunately, this current paradigm limits the ability to create sensors capable of high sensitivities and broad dynamic ranges as these materials are prone to saturation responses when attempting to obtain measurements involving high pressures. In this paper, we detail a piezoresistive pressure sensor that is capable of high sensitivity over a pressure range spanning from 0.6 Pa (a mosquito touching a surface) to 200 kPa (an elephant standing on the surface). The sensor's ability to cover such a broad dynamic range is made possible by the fairly hard foam used in its construction as this material is capable of propagating strain in a highly effective manner due to its hierarchical porous structure. The material was fabricated by using high-internal-phase emulsion (HIPE) as a template to generate a highly porous material consisting of small pores packed between larger ones whose inner walls are lined with reduced graphene oxide. The developed foam exhibits very fast response times (less than 15.4 ms) and excellent cyclic stability (at least 10,000 cycles). Furthermore, it is capable of responding to the entire tactile pressure range, and it can be formatted as pixelated arrays, which makes it highly suitable for integration into wearable electronic devices. Such arrays were built and used to identify and render the shape of objects with different geometries, including a sphere, a triangle, a square, and two nearly identical rods differing only by 0.4 mm in diameter.

The rapid development of soft electronics has revitalized the research of conducting elastomers. However, the design of conducting elastomers having high stretchability and good transparency still remains a considerable challenge. In this study, we develop a highly transparent, stretchable, and conducting ionoelastomer based on a poly­(ionic liquid) in which cations are fixed to a stretchable elastomeric network and counter anions are mobile. The ionoelastomer solves the dilemma of simultaneous transparency and stretchability in the design of traditional conducting elastomers, possessing good transparency (96%) with an extraordinarily high stretchability, up to a limiting strain of 1460%. Moreover, this novel material is completely nonvolatile and nonhygroscopic, endowing the ionoelastomer with highly stable thermal, environmental, electrochemical, and mechanoelectrical properties. An underwater sensor based on the ionoelastomer is developed with good performance in an aqueous environment. Also, a transparent dielectric elastomer actuator (DEA) is demonstrated using the ionoelastomer. It is believed that the ionoelastomer would pave the way to develop exceptional conducting elastomers toward next-generation soft electronics.

Using bismuth oxide (Bi2O3) as a laser-marking additive and thermoplastic polyurethane (TPU) as the matrix, TPU/Bi2O3 composite materials were prepared by melt blending in a torque rheometer. The sheet samples prepared from the TPU/Bi2O3 composites were treated in air by scanning with a neodymium-doped yttrium aluminum garnet (Nd: YAG) pulsed laser beam at a wavelength of 1064 nm. Compared with the pure TPU sample, the laser-marked composite samples exhibited differences in marking contrast as the Bi2O3 content increased from 0.1% to 1.0% based on stereomicroscope analysis. Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, thermogravimetry analysis, and X-ray diffraction were used to characterize the laser-marked surface material of the composite samples. Furthermore, a mechanism for the laser-effected darkening of the TPU/Bi2O3 composites was proposed. The results herein indicated that the addition of the Bi2O3 laser-sensitive additive to TPU resulted in laser darkening of the TPU/Bi2O3 composites. The marking contrast and visual appearance of the surface of the TPU/Bi2O3 composites after laser irradiation was due to a synergistic effect consisting of carbonization via TPU pyrolysis and reduction of Bi2O3 to black bismuth metal.