Polyethylene oxide (PEO) is one of the most widely used polymeric ion conductors which has the potential for a wide range of applications in energy storage. The enhancement of ionic conductivity of PEO-based electrolytes is generally achieved by sacrificing the mechanical properties. Using layer-by-layer (LbL) self-assembly with a nanoscale precision, mechanically strong and self-healable PEO/polyacrylic acid composite thin films with a high Li+ conductivity of 2.3 ± 0.8 × 10−4 S cm−1 at 30 °C, and a strength of 3.7 MPa is prepared. These values make the LbL composite among the best recorded multifunctional solid electrolytes. The electrolyte thin film withstands at least 1000 cycles of striping/plating of Li at 0.05 mA cm−2. It is further shown that the LbL thin films can be used as separators for Li-ion batteries to deliver a capacity of 116 mAh g−1 at 0.1 C in an all-LbL-assembled lithium iron phosphate/lithium titanate battery. Finally, it is demonstrated that the thin films can be used as ion-conducting substrates for flexible electrochemical devices, including micro supercapacitors and electrochemical transistors.

Gaining control over the nanoscale assembly of different electrode components in energy storage systems can open the door for design and fabrication of new electrode and device architectures that are not currently feasible. This work presents aqueous layer-by-layer (LbL) self-assembly as a route towards design and fabrication of advanced lithium-ion batteries (LIBs) with unprecedented control over the structure of the electrode at the nanoscale, and with possibilities for various new designs of batteries beyond the conventional planar systems. LbL self-assembly is a greener fabrication route utilizing aqueous dispersions that allow various Li+ intercalating materials assembled in complex 3D porous substrates. The spatial precision of positioning of the electrode components, including ion intercalating phase and electron-conducting phase, is down to nanometer resolution. This capable approach makes a lithium titanate anode delivering a specific capacity of 167 mAh g−1 at 0.1C and having comparable performances to conventional slurry-cast electrodes at current densities up to 100C. It also enables high flexibility in the design and fabrication of the electrodes where various advanced multilayered nanostructures can be tailored for optimal electrode performance by choosing cationic polyelectrolytes with different molecular sizes. A full-cell LIB with excellent mechanical resilience is built on porous insulating foams. 

Fiber-based biosensors enable a new approach in analytical diagnosticdevices. The majority of textile-based biosensors, however, rely oncolorimetric detection. Here a woven biosensor that integrates microfluidicsstructures in combination with an electroanalytical readout based on athiol-self-assembled monolayer (SAM) for Nucleic Acid Amplification Testing,NAATs is shown. Two types of fiber-based electrodes are systematicallycharacterized: pure gold microwires (bond wire) and off-the-shelf plasmagold-coated polyester multifilament threads to evaluate their potential to formSAMs on their surface and their electrochemical performance in woven textile.A woven electrochemical DNA (E-DNA) sensor using a SAM-based stem-loopprobe-modified gold microwire is fabricated. These sensors can specificallydetect unpurified, isothermally amplified genomic DNA of Staphylococcusepidermidis (10 copies/μL) by recombinase polymerase amplification (RPA).This work demonstrates that textile-based biosensors have the potential forintegrating and being employed as automated, sample-to-answer analyticaldevices for point-of-care (POC) diagnostics.

Herein, dual-tunable structural colors generated from liquid-infused, robust silsesquioxane aerogels due to the specific light scattering by the aerogel skeleton in liquids with matching refractive indices, are reported. The colors are tunable by changing the temperature and the composition of the liquid that roots from the coherence between the colors and the refractive index of the infused liquid. The finding provides new insights and tools for constructing structural colors and light management. It also opens applications of stimuli-responsive smart windows, displays, and sensors. Taking advantage of the penetrable light of selected wavelength, the 3D structures of aerogel skeletons are reconstructed by an optical method, which provides a facile alternative approach to characterizing aerogel structure and will be instrumental to the understanding of the relationship between skeleton structure and mechanical property of porous 3D structures.

Nucleic acid tests integrated into digital point-of-care (POC) diagnostic systems have great potential for the future of health care. However, current methods of DNA amplification and detection require bulky and expensive equipment, many steps, and long process times, which complicate their integration into POC devices. We have combined an isothermal DNA amplification method, recombinase polymerase amplification, with an electrochemical stem-loop (S-L) probe DNA detection technique. By combining these methods, we have created a system that is able to specifically amplify and detect as few as 10 copies/mu L Staphylococcus epidermidis DNA with a total time to result of 70-75 min.

Organic semiconductors are the centerpiece of several vibrant research fields from single-molecule to organic electronics, and they are finding increasing use in bioelectronics and even classical polymer technology. The versatile chemistry and broad range of electronic functionalities of conjugated materials enable the bridging of length scales 15 orders of magnitude apart, ranging from a single nanometer (10 −9 m) to the size of continents (10 6 m). This work provides a taste of the diverse applications that can be realized with organic semiconductors. The reader will embark on a journey from single molecular junctions to thin film organic electronics, supramolecular assemblies, biomaterials such as amyloid fibrils and nanofibrillated cellulose, conducting fibers and yarns for e-textiles, and finally to power cables that shuffle power across thousands of kilometers.

Layer-by-layer (LbL) assembly is a versatile tool for fabricating multilayers with tailorable nanostructures. LbL, however, generally relies on polyelectrolytes, which are mostly insulating and induce large interlayer distances. We demonstrate a method in which we replace polyelectrolytes with the smallest unit capable of LbL self-assembly: a molecule with multiple positive charges, tris(3-aminopropyl)amine (TAPA), to fabricate LbL films with negatively charged single-walled carbon nanotubes (CNTs). TAPA introduces less defects during the LbL build-up and results in more efficient assembly of films with denser micromorphology. Twenty bilayers of TAPA/CNT showed a low sheet resistance of 11 k Omega, a high transparency of 91% at 500 nm, and a high electronic conductivity of 1100 S/m on planar substrates. We also fabricated LbL films on porous foams with a conductivity of 69 mS/m and used them as electrodes for supercapacitors with a high specific capacitance of 43 F/g at a discharging current density of 1 A/g.

We report Layer-by-Layer (LbL) self-assembly of pillared two-dimensional (2D) multilayers, from water, onto a wide range of substrates. This LbL method uses a small molecule, tris(2-aminoethyl) amine (TAEA), and a colloidal dispersion of Ti3C2Tx MXene to LbL self-assemble (MXene/TAEA)(n )multilayers, where n denotes the number of bilayers. Assembly with TAEA results in highly ordered (MXene/TAEA)(n) multilayers where the TAEA expands the interlayer spacing of MXene flakes by only similar to 1 angstrom and reinforces the interconnection between them. The TAEA-pillared MXene multilayers show the highest electronic conductivity of 7.3 x10(4) S m(-1) compared with all reported MXene multilayers fabricated by LbL technique. The (MXene/ TAEA)(n) multilayers could be used as electrodes for flexible all-solid-state supercapacitors delivering a high volumetric capacitance of 583 F cm(-3) and high energy and power densities of 3.0 Wh L-1 and 4400 W L-1, respectively. This strategy enables large-scale fabrication of highly conductive pillared MXene multilayers, and potentially fabrication of other 2D heterostructures.