Roll-to-roll (R2R) processing enables the rapid fabrication of large-area sheets of cooperatively assembled materials for production of mesoporous materials. Evaporation induced self-assembly of a nonionic surfactant (Pluronic F127) with sol-gel precursors and phenolic resin oligomers (resol) produce highly ordered mesostructures for a variety of chemistries including silica, titania, and tin oxide. The cast thick (>200 μm) film can be easily delaminated from the carrier substrate (polyethylene terephthalate, PET) after cross-linking the resol to produce meter-long self-assembled sheets. The surface areas of these mesoporous materials range from 240 m(2)/g to >1650 m(2)/g with these areas for each material comparing favorably with prior reports in the literature. These R2R methods provide a facile route to the scalable production of kilograms of a wide variety of ordered mesoporous materials that have shown potential for a wide variety of applications with small-batch syntheses.

A roll-to-roll continuous process was developed to manufacture large-scale multifunctional poly(dimethylsiloxane) (PDMS) films embedded with thickness direction ("Z" direction) aligned graphite nanoparticles by application of electric field. The kinetics of particle "Z" alignment and chain formation was studied by tracking the real-time change of optical light transmission through film thickness direction. Benefiting from the anisotropic structure of aligned particle chains, the electrical and thermal properties of the nanocomposites were dramatically enhanced through the thickness direction as compared to those of the nanocomposites containing the same particle loading without electrical field alignment. With 5 vol % graphite loading, 250 times higher electrical conductivity, 43 times higher dielectric permittivity, and 1.5 times higher thermal conductivity was achieved in the film thickness direction after the particles were aligned under electrical field. Moreover, the aligned nanocomposites with merely 2 vol % graphite particles exhibit even higher electric conductivity and dielectric permittivity than those of the nonaligned nanocomposites at random percolation threshold (10 vol % particles), as the "electric-field-directed" percolation threshold concentration is substantially decreased using this process. As the graphite loading increases to 20 vol %, the aligned nanocomposites exhibit thermal conductivity as high as 6.05 W/m·K, which is 35 times the thermal conductivity of pure matrix. This roll-to-roll electric field continuous process provides a simple, low-cost, and commercially viable method to manufacture multifunctional nanocomposites for applications as embedded capacitor, electromagnetic (EM) shielding, and thermal interface materials.

We report the design of a series of polyesters containing pendant secondary amide groups to probe the cumulative effects of hydrogen bonding and chain flexibility on their thermal, mechanical, and rheological properties. Reported studies on polymers with secondary amide groups have usually focused on the effect of hydrogen bonding interactions on the mechanical, selfassembly, or self-healing properties, whereas the effect of chain flexibility has often been overlooked. In an effort to probe the cumulative effects of hydrogen bonding and chain flexibility, in this work polyesters were designed with either one or two pendant secondary amide-propyl groups and compared to a control polyester with one pendant ester-propyl group. The results show that hydrogen bonding increases glass transition temperature (T g ), Young's modulus, and polymer brittleness. But at higher temperature (T g + 50 °C), rheometry shows that the polyester containing two amide groups has the shortest chain relaxation time and the lowest zero-shear rate viscosity (η 0 ). These results are counterintuitive, since the polymer with two hydrogen bonding amide groups was expected to relax more slowly and have higher viscosity. Our results demonstrate the opposing effects of side-chain flexibility and hydrogen bonding interactions can be used as a strategy to design materials with desired rheological properties.

A roll to roll continuous processing method is developed for vertical alignment ("Z" alignment) of barium titanate (BaTiO3) nanoparticle columns in polystyrene (PS)/toluene solutions. This is accomplished by applying an electric field to a two-layer solution film cast on a carrier: one is the top sacrificial layer contacting the electrode and the second is the polymer solution dispersed with BaTiO3 particles. Flexible Teflon coated mesh is utilized as the top electrode that allows the evaporation of solvent through the openings. The kinetics of particle alignment and chain buckling is studied by the custom-built instrument measuring the real time optical light transmission during electric field application and drying steps. The nanoparticles dispersed in the composite bottom layer form chains due to dipole-dipole interaction under an applied electric field. In relatively weak electric fields, the particle chain axis tilts away from electric field direction due to bending caused by the shrinkage of the film during drying. The use of strong electric fields leads to maintenance of alignment of particle chains parallel to the electric field direction overcoming the compression effect. At the end of the process, the surface features of the top porous electrodes are imprinted at the top of the top sacrificial layer. By removing this layer a smooth surface film is obtained. The nanocomposite films with "Z" direction alignment of BaTiO3 particles show substantially increased dielectric permittivity in the thickness direction for enhancing the performance of capacitors.

A facile method to fabricate hierarchically structured fiber composites is described based on the electrospinning of a dope containing nickel and manganese nitrate salts, citric acid, phenolic resin, and an amphiphilic block copolymer. Carbonization of these fiber mats at 800 °C generates metallic Ni-encapsulated NiO/MnOx/carbon composite fibers with average BET surface area (150 m(2)/g) almost 3 times higher than those reported for nonporous metal oxide nanofibers. The average diameter (∼900 nm) of these fiber composites is nearly invariant of chemical composition and can be easily tuned by the dope concentration and electrospinning conditions. The metallic Ni nanoparticle encapsulation of NiO/MnOx/C fibers leads to enhanced electrical conductivity of the fibers, while the block copolymers template an internal nanoporous morphology and the carbon in these composite fibers helps to accommodate volumetric changes during charging. These attributes can lead to lithium ion battery anodes with decent rate performance and long-term cycle stability, but performance strongly depends on the composition of the composite fibers. The composite fibers produced from a dope where the metal nitrate is 66% Ni generates the anode that exhibits the highest reversible specific capacity at high rate for any composition, even when including the mass of the nonactive carbon and Ni(0) in the calculation of the capacity. On the basis of the active oxides alone, near-theoretical capacity and excellent cycling stability are achieved for this composition. These cooperatively assembled hierarchical composites provide a platform for fundamentally assessing compositional dependencies for electrochemical performance. Moreover, this electrospinning strategy is readily scalable for the fabrication of a wide variety of nanoporous transition metal oxide fibers.

Large-scale (multigram-to-kilogram) fabrication of soft-templated ordered mesoporous carbons (OMC) is enabled by roll-to-roll (R2R) processing via evaporation induced self assembly of Pluronic F127, oligomeric phenolic resin (resol), and tetraorthosilicate (TEOS) from ethanolic solution. The solution concentration, TEOS loading (etchable for microporous framework), and crosslinking temperature impact the pore structure. Here we demonstrate that mesoporous carbons with surface areas up to 2455 m 2 /g can be obtained under the proper processing conditions. Transmission electron microscopy (TEM), smallangle X-ray scattering (SAXS) and nitrogen adsorption-desorption isotherms reveal (i) supressed framework shrinkage with increasing solution concentration during casting, (ii) improved long range order and higher surface area with increasing TEOS content up to 3:1 TEOS:resol, and (iii) enhanced porosity with crosslinking at 100 ᵒC. These differences can be © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ 2 explained on the basis of block copolymer thermodynamics and mechanical reinforcement by silica. This family of OMCs are effective adsorbents for bulky aqueous organic dyes, such as methylene green (MG) and methyl blue (MB), with high adsorption capacities of 0.436 g MG/g OMC and 0.378 g MB/g OMC obtained. This R2R method provides a facile method to generate significant quantities of OMCs with tunable pore textures.

A combination of transparency, electrical conductivity and flexibility is desired in the emerging flexible electronics industry for current and future applications. In this paper, we report the development of through thickness electrical conductivity in polystyrene films filled with nickel nanopowder by external magnetic field application. This process leads to the formation of nanocolumns of nickel spanning across the thickness direction while generating nanoparticle depleted regions in between. This leads to directionally dependent enhancement in optical light transmission particularly in the normal direction of the films. With the use of as little as 2 wt% (0.22 vol%) nickel we were able to achieve high through thickness conductivity under the influence of a magnetic field. While these films exhibit high through thickness conductivity they remain non-conductive in their planes as a result of the unique nanomorphology created which eliminates potential side branch formations. These films are anticipated to be used as electrodes for touch screens, electric dissipative materials for electronic packaging and other sensors.

Cellulose paper-based materials are highly flexible, hydrophilic, low-cost, and environmentally friendly and are good substrates for use as humidity sensors. Therefore, developing a paper-based humidity sensor with facile fabrication, low cost, and high sensitivity is important for expanding its practical applications. Herein, we propose a CI/FP self-powered humidity sensor based on everyday items such as writing and drawing carbon ink (CI), cellulose filter paper (FP), and polyester conductive adhesive tape, which is fabricated with the help of facile dip-coating and pasting methods. This sensor is self-powered, and the paper-based material itself can absorb water molecules in a humid environment to generate humidity-related voltage and current, which can indirectly reflect the ambient humidity level. They are characterized by a wide relative humidity (RH) sensing range (11−98%), good linearity (R 2 = 0.97011), high response voltage (0.19 V), and excellent flexibility (over 1000 bends). This humidity sensor can be successfully applied to monitor human health (breathing, coughing), air humidity, and noncontact humidity sensing (skin, wet objects). This work not only proposes a low-cost and facile method for flexible humidity sensors but also provides a valuable strategy for the development of self-powered wearable electronics.