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Ionic liquid based fiber welding has been used to attach the metal–organic framework (MOF) UiO-66-NH2 to cotton fibers. The results show that by controlling the extent of the welding process, it is...

Ionic liquids (ILs) are becoming important solvents in commerce, but monitoring their purity and performance in industrial applications presents new challenges. Fiber welding technology utilizes ILs to mold and shape natural fibers (cotton, hemp, flax, silk, and wool) into morphologies that are typically attained only using synthetic, petroleum-based non-biodegradable plastics. The result is an atom-efficient process that up-converts fibrous substrates to value-added products and materials. A key aspect of bringing this and other IL-enabled technologies to market relies on efficient monitoring and recycling of IL-based solvents. Implementing online IL quality monitoring enhances the unit economics of these processes. Here, we characterize and report conductivity measurements, refractometry, and ATR-FTIR spectroscopy techniques for online IL monitoring during an industrial fiber welding process. The online analysis enables more efficient recycling of the IL solvent, increasing the process efficiency and product quality.

In their report ‘A New Textiles Economy: Redesigning Fashion’s Future’ (Ellen MacArthur 2017a), the Ellen MacArthur Foundation describes the need for the global textile industry to mobilize ‘moonshot’ innovations. Natural Fiber Welding (NFW) is a disruptive technology and materials company that is answering this call. In particular, NFW is developing technologies which enable abundant natural materials to be utilized in applications that are presently dominated by resource intensive plastics. In so doing, NFW is connecting production of textiles and other materials to regenerative agriculture. This has the potential of greatly reducing plastic pollution, significantly reducing the carbon footprint of the industry, and offers new cost-effective options for circularity—all while providing material performance and tunability that was not possible before.

In this work, we demonstrate the production of reactive, robust, sustainable catalysts for water treatment created through Natural Fiber Welding (NFW) of lignocellulose-supported palladium-indium (Pd-In) nanoparticles onto linen yarns. First, Pd-In catalysts were synthesized by incipient wetness onto ball-milled powders of linen. Our process preserved the lignocellulose, yielding small (5–10 nm), near-spherical crystalline nanoparticles of Pd-In alloy and a uniform Pd-In metal composition throughout the fibers. Nitrate reduction tests identified the existence of an optimum Pd-In catalyst composition (5 wt% Pd and 1.2 wt% In with respect to lignocellulose) for maximum reactivity; the most reactive Pd-In catalyst was 10 times more reactive than the best performing Pd-Cu nanoparticles deposited on lignocellulose using the same approach. This improved performance was most likely due to more uniform distribution of alloyed Pd-In nanoparticles throughout the support. Nitrate reduction tests and X-ray photoelectron spectroscopy depth profiling of aged Pd-In catalysts showed that they remained stable and lost no reactivity during extended storage in air at room temperature. Next, the optimized Pd-In catalyst was fiber-welded onto linen yarns, using a custom-built yarn-coating system and a novel, scalable process that controlled catalyst loading, delivering a Pd-In catalyst coating onto the yarn surface. This fiber-welded Pd-In catalyst yarn was integrated into a novel water treatment reactor and evaluated during four months and more than 180 h of nitrate reduction tests in ultrapure water. During this evaluation, the fiber-welded catalysts maintained their reactivity with negligible metal leaching. When tested in raw or (partially) treated drinking water and wastewater, the fiber-welded catalysts were robust and stable, and their performance was not significantly impacted by constituents in the complex waters (e.g. alkalinity, organic matter). Our research demonstrates an innovative, scalable approach through NFW to design and implement robust, sustainable lignocellulose-supported catalysts with enhanced reactivity capable of water purification in complex water chemistries.

Lignocellulosic composites (LCs) were fabricated by partially dissolving cotton to create a matrix that was reinforced with osage orange wood (OOW) particles and/or blue agave fibers (AF). LCs were composed of 15–35% cotton matrix and 65–85% OWW/AF reinforcement. The matrix was produced by soaking cotton wool in a cold aqueous alkaline/urea solvent and was stirred for 15 minutes at 350 rpm to create a viscous gel. The gel was then reinforced with lignocellulosic components, mixed, and then pressed into a panel mold. LC panels were soaked in water to remove the aqueous solvent and then oven dried to obtain the final LC product. Several factors involved in the preparation of these LCs were examined including reaction temperatures (−5 to −15°C), matrix concentration (15–35% cotton), aqueous solvent volume (45–105 ml/panel), and the effectiveness of employing various aqueous solvent formulations. The mechanical properties of LCs were determined and reported. Conversion of the cotton into a suitable viscous gel was critical in order to obtain LCs that exhibited high mechanical properties. LCs with the highest mechanical properties were obtained when the cotton wools were subjected to a 4.6% LiOH/15% urea solvent at −12.5°C using an aqueous solvent volume of 60 ml/panel. Cotton wool subjected to excessive cold alkaline solvents volumes resulted in irreversible cellulose breakdown and a resultant LC that exhibited poor mechanical properties.

Natural fiber welding is a process by which individual fibers are swollen by an appropriate ionic liquid-based solvent system to form a congealed network. Manipulated fibrous materials may be either composed of natural polymers such as cellulose, hemicellulose, silk, et cetera, or synthetic polymers, or mixed materials. The process is principally controlled by the composition of the solvent system which includes an ionic liquid solvent plus additives such as water, methanol, et cetera. Other conditions such as the amount and placement of solvent, as well as time, temperature, and pressure control the extent to which neighboring fibers are fused. Only the material at the outer surface of fibers need be sufficiently mobile to merge with that of neighboring fibers. Material in the fiber core may be left in the native state by controlling process variables. Fibers form a congealed network upon removal of the ionic liquid-based solvent.

In our study, lignocellulose yarns were fabricated via natural fiber welding (NFW) into a robust, free-standing, sustainable catalyst for water treatment. First, a series of powder catalysts were created by loading monometallic palladium (Pd) and bimetallic palladium–copper (Pd–Cu) nanoparticles onto ball-milled yarn powders via incipient wetness (IW) followed by a gentle reduction method in hydrogen gas that preserved the natural fiber while reducing the metal ions to their zerovalent state. Material characterization revealed Pd preferentially reduced near the surface whereas Cu distributed more uniformly throughout the supports. Although no chemical bonding interactions were observed between the metals and their supports, small (5–10 nm), near-spherical crystalline nanoparticles were produced, and a Pd–Cu alloy formed on the surface of the supports. Catalytic performance was evaluated for each Pd-only and Pd–Cu powder catalyst via nitrite and nitrate reduction tests, respectively. Next, the optimized Pd...

The utilization of ionic liquids (ILs) for future electrochemical applications shows great promise. Recently ILs have been investigated for many electrochemical systems however, further characterization and development of ILs remains as they are utilized in devices such as batteries, capacitors, fuel cells, sensors, and other applications. In this study, we present time resolved (TRS) FTIR spectroscopy data as a means to characterize interfaces between IL-based electrolytes and gold electrodes. These data are important in that dynamic interactions at the electrode/electrolyte interface are crucial to device efficiency, power density, sensitivity, et cetera.

Inkjet printing has become an increasingly popular tool for materials science research due to its ability to rapidly create small devices with excellent precision and reproducibility. Recent studies have utilized inkjet printing for the construction of inexpensive devices using ink-mimicking solutions containing various materials of interest (magnetic, sensing, electronic)[i],[ii],[iii]. By varying the chemical nature of these inks, inkjet printing becomes a robust, versatile, and accessible tool for small scale material fabrication. Ionic liquids (IL) have been the focus of materials research for some time due to their unique physical and chemical properties. Of significant interest is their ability to solubilize biopolymers such as cellulose and silk[iv]. When paired with inkjet printing, these ILs allow for variable, reproducible modification of biopolymers. By incorporating materials of interest into these IL inks, inkjet printing presents an extremely powerful tool for small scale fabrication with a myriad of applications. In this research we will discuss the modification of surface structures through the inkjet printing of neat IL, IL’s containing nano and micro-scale particles, and IL/polymer solutions. [i] Delaney, J. T., Jr.; Smith, P. J.; Schubert, U. S. Inkjet Printing of Proteins. Soft Matter, 2009, 24, 4866. [ii] Singh, M.; Haverinen, H. M.; Dhagat, P.; Jabbour, G. E. Inkjet Printing – Process and Its Applications. Adv. Materials, 2010, 22, 673. [iii] Hu, C.; Bai, X.; Wang, Y.; Jin, W.; Zhang, X.; Hu, S. Inkjet Printing of Nanoporous Gold Electrode Arrays. Anal. Chem. 2012, 84, 3745. [iv] Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. Dissolution of Cellulose with Ionic Liquids. J. Am. Chem. Soc., 2002, 18, 4974.

Batteries are one of the most impactful inventions humankind has ever developed. Lithium-ion energy cells represent a significant advance in battery technology. Electrolytes used in batteries are still not well understood in terms of solution structure. We investigate electrolyte solvate structure with the aid of differential scanning calorimetry, Raman spectroscopy, and X-ray diffraction. Here is a report on the solvate structure(s) present in mixtures of propylene carbonate (PC) and lithium trifluoromethanesulfonate (LiTf). Mixtures of racemic PC with LiTf form glasses whereas enantiomerically pure PC, both R and S isomers, forms mixtures with more complex phase behavior. At concentrations approaching a 1:1 molar ratio of solvent to salt, a solvate that melts at ~150 °C was detected. A crystal of the 1:1 solvate of the R-(+)-PC:LiTf was successfully grown and analyzed by X-ray diffraction. This solvate has an aggregated structure where the Li+ cations are tetrahedrally coordinated. Three directions of coordination come from Tf– anions acting as a bridging ligand between three different Li+ cations and the 4th direction of coordination comes from the carbonyl oxygen of the solvent molecule.

Extruded organically modified layered silicate (OMLS) - poly(lactic acid) (PLA) composites exhibit a mixed intercalated/exfoliated morphology. To explore effects of surfactant hydrophobicity and polarity on the quality of dispersion, a series of OMLS were prepared from quaternary ammonium, phosphonium, and imidazolium salts, including some synthesized hexadecanoic acid containing ionic liquids. The alkyl chains were modified to include aromatic and oxygen moieties while keeping the same long alkyl chain length. Nile Blue was co-exchanged to add a fluorescent tag to the layered silicates. The effectiveness of this technique for PLA and different Nile Blue salts were assessed. Degree of exfoliation was monitored using x-ray diffraction and fluorescence spectroscopy. Thermal characteristics of the new OMLS were measured.

Ionic liquids (ILs) represent a class of printable material for use in the inkjet technique. Additionally, some ILs are effective solvents for biopolymers (i.e., cellulose and silk). The combination of the ILs ability to solvate biopolymers and the highly controllable delivery of liquids utilized in inkjet printing technology provide a means to pattern substrates and build structures. In this report, the delivery of IL-based solvents to cellulosic papers by inkjet printing is demonstrated. In particular, imaging data that characterize morphological alterations to cellulosic paper substrates are discussed. Results suggest that printed materials with unique properties are possible for a wide range of applications.

In the past decade, ionic liquid solvents have been developed for a wide variety of biopolymers such as cellulose and silk. During this time ionic liquids have also been shown to enhance the interactions of micromaterials and nanomaterials (i.e., clays, carbon nanotubes, magnetic materials, et cetera) with polymeric materials. Recently, our group has demonstrated an ionic liquid-based technique, “Natural Fiber Welding”, by which functionalized composite materials are generated from (often fibrous) biopolymer substrates. Fiber welding processes leverage many of the advantageous properties of ionic liquids as solvents and compatibilization media. A distinctive characteristic of the fiber welding process is the selective mobilization and restructuring of biopolymers to create composite materials that retain native biopolymer microstructures and mesostructures. As ionic liquid solvents penetrate fiber surfaces, biopolymers are opened to chemical derivatization; simultaneously, hydrogen bonding networks are reorganized (and extended).

Certain ionic liquids (ILs) are known to be efficient solvents for biopolymers. That said, solvent efficacy is strongly impacted by the presence of both adventitious as well as other molecular components that may be added deliberately. For example, 1-ethyl-3-methylimidazolium acetate often contains water and acetic acid (polar protic) impurities (by-products of IL synthesis) that can have significant effects upon the dissolution of biopolymers. Additionally, ILs can be mixed with solvents such as acetonitrile (polar aprotic) that also impact the dissolution process. Data are presented that explore the effect of IL-based solvent composition on fiber welding: the controlled, partial dissolution of fibrous materials to create composite materials. Results suggest that IL-based solvents can be modified for specific outcomes. Additionally, the fiber welding processes and material analysis techniques utilized are themselves useful to quantify solvent efficacy.

Electrospinning is a technique commonly used to produce nano to micro sized fibers with a high surface area to volume ratio. Of particular interest are electrospun natural fibers, such as cellulose, with high biocompatibility allowing for applications in biosensors, membranes and biomedical devices. Unfortunately, cellulose is naturally recalcitrant and insoluble in common solvents due to high crystallinity arising from a strong hydrogen bonding network making processing of this fiber difficult. Currently, processing techniques such as wet or dry-wet spinning and electrospinning have been investigated with known cellulose solvent such as Nmethyl-morpholine N-oxide/water, salt/solvent systems such as lithium chloride/dimethyl acetamide or ethylene diamine/potassium thiocyanate, ionic liquids (ILs) and from IL/dimethylsulfoxide systems.

Cellulose-reinforced composites have received much attention due to their structural reinforcing, light weight, biodegradable, non-toxic, low cost and recyclable characteristics. However, the tendency for cellulose to aggregate and its poor dispersion in many polymers, such as polystyrene, continues to be one of the most challenging roadblocks to large scale production and use of cellulose-polymer composites. In this study, nanofibrillated cellulose (NFC) is modified using GlycidylPhenyl-POSS (a polyhedral oligomeric silsesquioxane). The product yield, morphology, and crystallinity are characterized using a variety of spectroscopy and microscopy techniques. Thermal analyses are performed using thermal gravimetric analysis and pyrolysis combustion flow calorimetry.

A systematic study of variables that affect the fiber welding process is presented. Cotton cloth samples are treated with controlled amounts of 1-ethyl-3-methylimidazolium acetate for a series of times and temperatures. Diluting the ionic liquid with a volatile molecular co-solvent allows temporal and spatial control of the welding process not possible with neat ionic liquids. Materials are characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and mechanical (tensile) testing. Results suggest careful management of process variables permits controlled, reproducible manipulation of chemical and physical properties.

Fossil fuels are being rapidly depleted and a novel and renewable source of hydrocarbons needs to be found. One source of untapped energy is cellulose. Work has shown that ionic liquids can dissolve and enable the facile processing of cellulose. This research shows that 1-methylimidazolum-3-ethylsulfonic acid triflate, an ionic liquid catalyst, can be used as a catalyst for the depolymerization of cellulose in an ionic liquid at greater than 50% conversion to reducing sugars. It also shows the main product of the reaction is glucose which is further dehydrated into 5-(Hydroxy-methyl) furfural. This investigation evaluated the effects of time, temperature, and co-catalyst on the reaction products and rate of the reaction.

Preliminary data are shown for a systematic study of the variables that control the fiber welding process. Cotton cloth samples are treated with various amounts of 1-ethyl-3-methylimidazolium acetate for a series of times and temperatures. Processed materials are characterized by scanning electron microscopy, infrared spectroscopy, x-ray diffraction, and mechanical (tensile) testing. Chemical and physical properties are shown to be controllably modified with careful management of process variables.

Ionic liquids are effective solvents for the dissolution of biopolymers such as cellulose and silk. New materials can be created from these natural feedstocks by processes that involve the full dissolution of biomaterials. Many reports show that the dissolution and reconstitution processes eliminate the native polymer structure, often with deleterious consequences to the physical properties of the material. Recently, it has been shown that robust biopolymer based structures may be created without full dissolution of the material by a method we call “Natural Fiber Welding”. The welding process generates modified natural fiber structures while leaving much of the material in its native state. As a result, natural fiber welding enables tunable preservation of native microstructure while also affording manipulation of important material properties.

Natural Fiber Welding (NFW) is an Ionic Liquids (IL) based engineering process that can manipulate biopolymer matrices without destroying their underlying structure. It can be used to incorporate functional materials into the biopolymer matrix. In this study, we evaluate how NFW can be used to improve the thermal stability of natural textile fibers. First, a variety of synthesized and/or commercially available flame-retardant micro/nanomaterials are welded onto the surface of the fibers. Then, using thermogravimetric (TG) analysis, we demonstrate how each coating can enhance the thermal stability of the textile yarn. In some cases, thermal stability improves by as much as 25 °C, primarily through delays in the onset of thermal decomposition and increased char yield. Our data reveal strong potential for NFW to be used to deliver fiber-welded textile yarns with improved thermal stability.

Ionic liquids (IL) have been shown to be effective solvents for the dissolution of a wide variety of natural polymers, and new materials can be created from these natural feedstocks by processes that involve their full dissolution and subsequent reconstitution. Yet, the dissolution and reconstitution processes eliminates the native polymer structure often resulting in materials with significantly degraded physical properties when compared to the native material. However, if only the surface layers of these natural materials are mobilized through an ionic liquid facilitated process called Natural Fiber Welding (NFW), the underlying material retains its native character and mechanical properties while still allowing for significant material modification. Furthermore, the addition of functional materials (e.g. magnetic, optical, conductive) into the IL welding solution, allows for these substances to be entrained in and on the surface of the substrate imparting unique properties to the natural materials. In this work metallic nanoparticles were synthesized in linen powders by the process of incipient wetness impregnation. The linen containing nanoparticles were added to an IL and then welded to the surface of a natural polymer substrate (e.g., cotton yarn) via NFW. The morphology of the welded materials and the distribution of nanoparticles was characterized with TEM, SEM, and fluorescent imagery. Raman and infrared spectroscopies were used to evaluate the impact of the nanomaterials on the spectroscopic properties of the biocomposites, and atomic force microscopy and tensile strength testing were used to evaluate the mechanical properties of prepared composites. Using a variety of magnetic measurement techniques, we explored how nanoparticle composition and structure relate to each systems observed magnetic properties, and how some show nanomagnetic behavior at low temperature. Overall, the prepared composites maintained many of the attractive properties of the native substrates, while still exhibiting the functional properties of the entrained materials.

Preliminary data are shown for the mechanical properties of cellulose and silk composite blends with and without nanomodifiers. Composite strength increases with increasing cellulose concentration for samples created with two different coagulation solutions. In general, samples containing > 30% silk are difficult to handle and test because they are extremely brittle. The addition of nanocomposites may increase overall strength of samples, but is dependent on the morphology of the nanomaterial added.

This report details the procurement and integration of an infrared (IR) spectrometer (Thermo Scientific - Nicolet iS50R Spectrometer) intoour electrochemistry program. The instrument is being utilized to characterize ionic liquid-based (IL-based) electrolyte systems viasimultaneous electrochemical and spectroscopic studies. These studies are enabling us to understanding the microscopic (molecular andionic) dynamics at electrolyte/electrode interfaces. This information is important for the development of enhanced energy conversionprocesses and devices (e.g., supercapacitors). The Nicolet iS50R spectrometer has been synchronized with a potentiostat to perform surfaceenhanced infrared absorption (SEIRA) spectroscopy during electrochemical (voltammetric) perturbation. The spectrometer has also beenutilized to help us characterize biomaterials before and after processing in a separate project that aims to create robust, functionalbiocomposites. In particular, we are interested to develop tough bio-based composites for energy storage and water remediationapplications. Sample data from these ongoing efforts are demonstrated in this report.

Lignocellulosic composites (LCs) were prepared by partially dissolving cotton along with steam exploded Aspen wood and burlap fabric reinforcements utilizing an ionic liquid (IL) solvent. Two methods of preparation were employed. In the first method, a controlled amount of IL was added to preassembled dry matrix of cotton and Aspen wood with a burlap weave reinforcement. In the second method, IL solvent, cotton, and Aspen wood were mixed to produce a thick paste matrix that was subsequently pressed into the burlap weave reinforcement. The IL-based solvent was removed via water soaking, and the flexural and tensile properties of the LCs were examined. In this study, the matrix paste method produced a superior LC. Variables such as processing time (IL interaction time) and fabric weaves were found to influence the mechanical properties of the LCs. Although significant process optimization can still be realized, the mechanical properties of several of the LCs fabricated in this study were comparable to injection molded test specimens of neat high density polyethylene or neat polypropylene.

Dissolution and depolymerization of cellulose by the action of acid-functionalized ionic liquid catalysts is reported. Depolymerization of microcrystalline cellulose (MCC) was accomplished by utilizing a binary IL system composed of an IL solvent, 1-butyl-3-methyl-1H-imidazolium chloride (C4mim-Cl), capable of cellulose dissolution combined with a homogeneous IL acid catalyst. The sulfonic acid functionalized IL catalysts employed are capable of hydrolyzing glycosidic bonds to yield cellobiose, glucose and that also enabled dehydration reactions producing 5-hydroxymethylfurfural. Viscometry was employed to follow the progress of the depolymerization and follow-on derivatization reactions. Experiments yielded real-time viscosity data of the reaction system which indicated the type and timing of the derivatization processes that occur. Results suggest that viscometric analyses can be a useful methodology to rapidly screen solution/catalyst compositions for desired outcomes.

A technique was developed for preparing a novel material that consists of gold nanoparticles trapped within a fiber of unfolded proteins. These fibers are made in an aqueous solution that contains HAuCl4 and the protein, bovine serum albumin (BSA). By changing the ratio of gold to BSA in solution, two different types of outcomes are observed. At lower gold to BSA ratios (30–120), a purple solution results after heating the mixture at 80 °C for 4 h. At higher gold to BSA ratios (130–170), a clear solution containing purple fibers results after heating the mixture at 80 °C for 4 h. UV–Vis spectroscopy and light scattering techniques show growth in nanocolloid size as gold to BSA ratio rises above 100. Data indicate that, for the higher gold to BSA ratios, the gold is sequestered within the solid material. The material mass, visible by eye, appears to be an aggregation of smaller individual fibers. Scanning electron microscopy and transmission electron microscopy indicate that these fibers are primarily one-dimensional aggregates, which can display some branching, and can be as narrow as 400 nm in size. The likely mechanism for the synthesis of the novel material is discussed.

Throughout history humankind has exploited the remarkable properties of natural polymers such as silk and cellulose. In modern times, these natural materials still possess properties that rival the most advanced synthetic polymers. Recent work has shown ionic liquids (IL) to be effective solvents for the dissolution of a wide variety of natural polymers, and new materials can be created from these natural feedstocks by processes that involve their full dissolution and subsequent reconstitution. However, many reports show that the dissolution and reconstitution processes eliminate the native polymer structure, often with negative consequences to the physical properties of the resulting materials. Alternatively, if only the surface layers of these natural materials are mobilized through an ionic liquid facilitated process called Natural Fiber Welding (NFW), the underlying material retains its native character and mechanical properties while still allowing for significant material modification. Furthermore, the addition of functional materials (e.g. magnetic, conductive, antimicrobial) into the IL welding solution, allows for these substances to be entrained in and on the surface of the substrate imparting unique properties to the natural materials. Our group has endeavored to utilize NFW to modify natural materials to introduce novel functionalities. This work has encompassed the incorporation of a wide variety of polymeric, organic and inorganic materials into natural fiber matrices. Through the introduction of the appropriate materials we have been able to impart capacitive, conductive, catalytic, magnetic, optical, antimicrobial, and/or fire retardant functionalites into natural polymeric materials. In this presentation we will show our most recent efforts utilizing NFW to prepare novel functional natural materials.

We will present data for experiments that probe structure and dynamics at ionic liquid (IL) and ionic liquid-based (IL-based) systems with electrode interfaces. IL-based electrolytes have been investigated for applications ranging from energy conversion devices (e.g., capacitors, batteries, fuel cells, and solar cells) to sensors. Fundamental characterizations of IL-based electrolyte/electrode systems can contribute toward engineered progress for these enterprises since adsorbed species and their associated interfacial dynamics play critical roles in determining device efficiencies. Our studies utilize surface enhanced infrared absorption (SEIRA) spectroscopy. In particular, we demonstrate hyperspectral imaging at an attenuated total reflectance crystal that has been modified with a nanostructured gold electrode. Imaging experiments characterize interfacial structure and dynamics between several ionic liquid media (compositions) at the electrode surface simultaneously during electrochemical perturbation. Our initial spectral imaging studies explore ILs composed of imidazolium-based cations with alkylsulfate, tetrafluoroborate, thiocyanate, dicyanamide, and bis(trifluoromethylsulfonyl)imide anions.

Natural fiber welding (NFW) is a process that uses controlled amounts of ionic liquid and molecular co-solvent(s) to swell and mobilize portions of a natural polymer substrate. By carefully selecting factors controlling NFW such as time, temperature and solvent system composition, partial dissolution occurs, mobilizing and redistributing only a small portion of the natural polymer and leaving much of the underlying substrate intact. The NFW process results in fibers with a shell of dissolved/mobilized polymer, permanently adhered to both the outer diameter of the fiber and (depending on the extent of welding) to the surface of adjacent fibers. When polymeric and/or particulate materials are added during the NFW process, these substances can be integrated into the natural polymer matrix and modify its properties to include novel functionalities. In the present work we have applied the NFW process to the modification of natural polymer yarns. We have studied the processing conditions that impact the NFW of natural polymer yarns and the accompanied incorporation of functional materials (e.g., magnetic, conductive, and capacitive). We will discuss the preparation these functionalized yarns, and we will show data for their analysis using tensile testing, infrared spectroscopy, and scanning electron and con-focal fluorescence microscopies.

Ionic liquid-facilitated mobilization and reorganization of biopolymers in natural fibrous materials is visualized by confocal fluorescent spectromicroscopy. Ionic liquid-based processes controllably fuse adjacent fibres while simultaneously leaving selected amounts of biopolymers in their native states. These processes generate congealed materials with extended intermolecular hydrogen bonding networks and enhanced properties.

Applications of novel thin film electrodes are enabling the development of new commercial products ranging from in vivo biosensors, solar cells, and lithium-ion energy storage. A critical consideration that enables informed engineering of working devices is mass transport of electro-active species (EAS) and electrolytes within porous thin film electrodes. Initially we focus on the fabrication and characterization of transport within thin film electrodes fabricated from titanium dioxide, hydrogen titantate nanotubes, and zinc oxide via a sol-gel method. Characterization data for films deposited on indium tin oxide coated glass slides by doctor blade techniques are also discussed and include bright field microscopy, powder x-ray diffraction and, mass transport properties as investigated by cyclic voltammetry. Additionally we will discuss the creation and characterization of graphene nanosheets via the reduction of graphite oxide.

The utilization of ionic liquids (ILs) for future electrochemical applications shows great promise. Recently ILs have been investigated for many electrochemical systems however, further characterization and development of ILs remains to be accomplished before they are applied to devices such as batteries, capacitors, and fuel cells. For example, data that yield understanding of the interfacial structure and dynamics of ILs at electrode surfaces are vital since these interactions ultimately allude to electrochemical device efficiency. We will present data from time resolved (TRS) FTIR spectroscopy coupled with cyclic voltammetry as a means to characterize interfaces between IL-based electrolytes and metal electrode surfaces.

Natural fiber welding (NFW) is a method whereby solvent blends and process conditions are tailored to selectively swell and mobilize the biopolymers of fibrous, natural materials for functional (chemical and physical) modification.1-4 For example, careful control of solvent to substrate ratio, solvent composition (efficacy), as well as the time, temperature, pressure, and location of solvent exposure results in robust composites composed of fibrous substrates that are fused without glues or resins. The biopolymers within the cores of individual fibers may be demonstrated to retain their native structures and thus functionalities. In addition to unique fiber blends, other materials such as conductive carbons, magnets, fire retardants, et cetera may be incorporated during processing to yield highly functional composites that are sustainably produced and exhibit low embodied energy. In this presentation, we will discuss NFW processes to create flexible carbon-containing yarns for wearable supercapacitor applications. In particular, repeatable, scalable processes that generate composites that perform on par with similar state of the art devices reported in the literature. Given that these composites are based on truly ‘green’ cellulosic and lignocellulosic substrates (cotton and bamboo) and utilizing a nonfluorinated binder (cellulose from cotton), we believe this to be a significant breakthrough for the prospects of wearable energy storage.5-8 In addition, we will discuss the prospects for large scale nonwoven bio-based electrodes produced from inexpensive agricultural wastes and suitable for any number of important applications (e.g., filtration of pollutants from air and water). Acknowledgements: Portions of this work were funded by the Air Force Office of Scientific Research. Any opinions, findings, conclusions or recommendations expressed in the material are those of the authors and do not necessarily reflect the views of the U.S Navy or U.S Air Force. K. Jost acknowledges support from the DoD National Defense Science and Engineering Graduate (NDSEG) Fellowship. References: (1) L. M. Haverhals, W. M.Reichert, H. C. De Long, P. C. Trulove, Macromol. Mater. Eng., 2010, 295, 425-430. (2) L. M. Haverhals, H. M. Sulpizio, Z. A. Fayos, M. A. Trulove, W. M. Reichert, M. P. Foley, H. C. De Long, P. C. Trulove, ECS Transactions, 2010, 33, 79-90. (3) L. M. Haverhals, H. M. Sulpizio, Z. A. Fayos, M. A. Trulove, W. M. Reichert, M. P. Foley, H. C. De Long, P. C. Trulove, Cellulose, 2012, 19, 13-22. (4) L. M. Haverhals, L. M. Nevin, M. P. Foley, E. K. Brown, H. C. De Long, P. C Trulove, Chem. Commun., 2012, 48, 6417-6419. (5) Simon, P. & Gogotsi, Y. Nature Materials, 2009, 7, 845-854; (6) Jost, K. et al. Energy and Environmental Science 2011, 4, 5060-5067. (7) Jost, K. et al. Energ Environ Sci., 2013, 6, 2698–2705. (8) K. Jost, D. P. Durkin, L. M. Haverhals, E. K. Brown, M. Langenstein, H. C. De Long, P. C. Trulove, Y. Gogotsi, G. Dion, Adv. Energy Mater., 2015, 5, 1401286.

Ionic liquids (ILs) are potentially ‘game changing’ electrolytes for energy conversion applications such as capacitors [i] ,[ii] , batteries [iii] ,[iv] , fuel cells [v] ,[vi] , and solar cells. [vii] ,[viii] Significant progress has been made towards utilizing these remarkably adaptable materials for specific applications however, much work remains to generate technologically and economically relevant devices and processes.[ix] Characterizations of interfaces between IL-based electrolyte/electrode systems are crucial to continued development for these enterprises. In specific, detailed descriptions and understanding of structure and dynamics at electrolyte/electrode interfaces are necessary to realize engineered progress because device efficiencies are often largely determined by processes that occur at the interface. [x] ,[xi] Our presentation will focus on initial efforts to employ spectroscopic techniques that characterize interfacial structure and dynamics between ionic liquid media and electrode surfaces during simultaneous electrochemical perturbation. In specific, we will present surface enhanced infrared absorption (SEIRA) spectroscopy data for ILs composed of imidazolium-based cations with bis(trifluoromethylsulfonyl)imide anions at nanostructured noble metal electrodes (i.e, Au). [i]. T. Sato, G. Masuda, K. Takagi, Electrochim. Acta, 2004, 49, 3603-3611. [ii]. A. Orita, K. Kamijima, M. Yoshida, J. Power Sources, 2010, 195, 7471-7479. [iii]. A. S. Best, A. I. Bhatt, A. F. Hollenkamp, J. Electrochem. Soc., 2010, 157, A903-A911. [iv]. J.-K. Kima, A. Matica, J.-H. Ahnb, P. Jacobsson, J. Power Sources, 2010, 195, 7639-7643. [v]. S.-Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc., 2010, 132, 9764-9773. [vi]. M. Guo, J. Fang, H. Xu, W. Li, X. Lu, C. Lan, K. Li, J. Membr. Sci., 2010, 362, 97-104. [vii]. P. K. Singh, N. A. Jadhav, S. K. Mishra, U. P. Singh, B. Bhattacharya, Ionics, 2010, 16, 645-648. [viii]. C.-P. Lee, P.-Y. Chen, R. Vittal, K.-C. Ho, J. Mater. Chem., 2010, 20, 2356-2361. [ix]. M. Armand, F. Endres, D. R. MacFarlane, H. Ohno, B. Scrosati, Nature Materials, 2009, 8, 621-629. [x]. A. J. Bard, L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, 2nd ed., 2002, John Wiley & Sons, Inc., New York, NY. [xi]. M. Yoshida, A. Yamakata, K. Takanabe, J. Kubota, M. Osawa, K. Domen, J. Am. Chem. Soc., 2009, 131, 13218-13219.

The utilization of ionic liquids (ILs) for future electrochemical applications shows great promise. Recently ILs have been investigated for many electrochemical systems however, further characterization and development of ILs remains to be done before they are applied to devices such as batteries, capacitors, and fuel cells. For example, data that yield understanding of the interfacial structure and dynamics of ILs at electrode surfaces are vital since these interactions ultimately allude to electrochemical device efficiency. We will present time resolved (TRS) FTIR spectroscopy data as a means to characterize IL-based electrolytes. In particular, we will exhibit two modes of TRS: step scanning and rapid scanning during simultaneous electrochemical perturbation to better understand IL interactions at metal electrode surfaces.

Ionic liquids (IL) have been the focus of materials research for some time due to their unique physical and chemical properties. Of significant interest is their ability to solubilize biopolymers such as cellulose, chitin, keratin, and silk. However, full dissolution and regeneration using IL solvents often results in biomaterials with inferior properties compared to the native material. When natural substrates are only partially dissolved and regenerated through a process called Natural Fiber Welding (NFW), much of the native biomaterial structure can be maintained while still opening up the outermost portion of fibers so that the physical and chemical properties may be manipulated and/or modified. Furthermore, if functional materials (e.g. magnetic, conductive, capacitive, antimicrobial) are present in the IL-welding solution, these materials may be entrained in and on the surface of the fiber substrate. In the present work we will discuss the spatially controlled application of the NFW process and how this can be used to generated novel conductive and capacitive structures.

Development of novel thin film electrodes may enable new commercial products ranging from in vivo biosensors to solar cells. A critical consideration that assists the engineering of working devices is mass transport of electro-active species and solvent/electrolytes within porous thin film electrodes. Our presentation will focus on the fabrication and characterization of transport within thin film electrodes fabricated from titanium dioxide nanospheres, nanorods and nanotubes via sol-gel methods. We will present initial characterization data for films deposited on indium tin oxide coated glass slides by doctor blade techniques. Results include bright field and phase microscopy characterizations that probe the pore structure, surface morphology, and that yield physical dimensions of the films. Electron microscopy data will be presented that characterize particle dimensions and morphological differences resulting from multiple processing procedures. Powder x-ray diffraction data will be presented that investigate the crystal structure of the semiconducting films. Finally, mass transport properties as investigated by cyclic voltammetric techniques will be presented. Results will be correlated with fabrication techniques and associated material types and morphologies.

Certain ionic liquids (ILs) are known to be efficient solvents for biopolymers, in particular for cellulosic and silk based materials1. The ionic liquid solvent efficiency is strongly impacted by the presence of both impurities (e.g., water, residual reagents) and intentional additives (e.g., co-solvents or diluents)3,4. Natural fiber welding (NFW), the process of controlled partial dissolution and regeneration of biopolymers,5-7 is also affected by the presence of impurities and additives8. In this work we investigate the impact of impurities and additives on NFW. The extent of NFW was characterized by x-ray diffraction, ATR-IR, SEM, and mechanical property testing. These data are correlated with solvent physical properties, such as viscosity, density, and surface tension, as well as with solvent properties as indicated by their Kamlet-Taft parameters. For some of the systems investigated, there is a maximum solvent composition where polar aprotic solvents in conjunction with IL are more efficient at NFW than the IL alone. Surprisingly, this composition occurs when the mole ratio of IL to solvent is less than one to one. Understanding the factors that influence welding in these systems allows for greater control over the NFW process and facilitates the formation of functional biopolymer composite materials. References Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. J. Am Chem Soc, 2002, 124, 4974. Phillips, D. M.; Drummy, L. F.; Conrady, D. G.; Fox, D. M.; Naik, R. R.; Stone, M. O.; Trulove, P. C.; De Long, H. C.; Mantz, R. A. J Am Chem Soc., 2004, 126, 14350. Rinaldi, R. Chem. Commun., 2011, 47, 511. Mazza, M.; Catana, D. A.; Vaca-Garcia, C.; Cecutti, C. Cellulose, 2009, 16, 207. Haverhals, L. M.; Reichert, W. M.; De Long, H. C.; Trulove, P. C. Cellulose, 2010, 2985, 425. Haverhals, L. M.; Sulpizio, H. M.; Fayos, Z. A.; Trulove, M. A.; Reichert, W. M.; Foley, M. P.; De Long, H. C.; Trulove, P. C.Cellulose, 2012, 19, 13. Haverhals, L. M.; Nevin, L. M.; Foley, M. P.; Brown, E. K.; De Long, H. C.; Trulove, P. C. Chem.Commun., 2012, 48, 6417. Haverhals, L. M.; Brown, E. K.; Foley, M. P.; De Long, H.; Trulove P. ECS Trans, 2012, 50, 6

As excellent solvents for cellulose and silk, certain ionic liquids (ILs), such as 1-ethyl-3-methylimidazolium acetate (EMIAc),1,2 can be used for biopolymer modification and manipulation. Full dissolution and regeneration using IL solvents often results in biomaterials with inferior properties compared to the native material. When natural substrates are only partially dissolved and regenerated through a process we call Natural Fiber Welding (NFW), much of the native biomaterial structure can be maintained while still allowing for significant material modification. NFW enables the structural modification of the surface and incorporation of functional materials through the binding capability of the portion of dissolved biopolymer3-5. In the present work we have employed a laser as the heat source to initiate partial dissolution of a cellulose substrate causing NFW in a spatially-specific manner. By using a non-solvent for cellulose (e.g., water) with the ionic liquid as a means of inhibiting the dissolution process, heat becomes the controlling factor necessary to obtain significant biopolymer dissolution and mobilization. A CO2 laser was used to raster a specific pattern onto a cellulosic paper substrate coated with IL solution. Raster power, concentration of the ionic liquid and the number of laser passes affect the amount of heat absorbed into the biopolymer and the level of NFW. Through tensile testing, confocal microscopy, ATR-IR, and SEM imaging, the resulting modification of the biopolymers was characterized. References Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. J. Am Chem Soc, 2002, 124, 4974. Phillips, D. M.; Drummy, L. F.; Conrady, D. G.; Fox, D. M.; Naik, R. R.; Stone, M. O.; Trulove, P. C.; De Long, H. C.; Mantz, R. A. J Am Chem Soc., 2004, 126, 14350. Haverhals, L. M.; Reichert, W. M.; De Long, H. C.; Trulove, P. C. Cellulose, 2010, 2985, 425. Haverhals, L. M.; Sulpizio, H. M.; Fayos, Z. A.; Trulove, M. A.; Reichert, W. M.; Foley, M. P.; De Long, H. C.; Trulove, P. C.Cellulose, 2012, 19, 13. Haverhals, L. M.; Nevin, L. M.; Foley, M. P.; Brown, E. K.; De Long, H. C.; Trulove, P. C. Chem.Commun., 2012, 48, 6417.

In this application, an ionic liquid (IL), specifically 1-ethyl-3-methylmidazolium acetate (EMIAc), well known for its ability to dissolve a variety of biopolymers1-3, is used in conjunction with molecular co-solvents to prepare biopolymer composite yarns by a process we call natural fiber welding (NFW). NFW uses controlled amounts of IL and a molecular co-solvent to swell and mobilize portions of the biopolymer substrate. By carefully selecting factors controlling NFW such as time, temperature and solvent system composition, partial dissolution occurs, mobilizing and redistributing only a small portion of the natural fibers and leaving much of the underlying substrate intact.4-7 This results in fibers with a shell of dissolved polymer, permanently adhered and hydrogen bonded to both the outer diameter of the fiber and (depending on the extent of welding) to the surface of adjacent fibers. With the addition of a small amount of biopolymer into the IL solution, a NFW composite yarn can be created with the pre-dissolved biopolymer acting as an additional binder. Different combinations of biopolymer binder and substrate take advantage of the functional and structural benefits of both biopolymers. Binder can also be used to facilitate incorporation of functional materials (e.g., magnetic, electronic, photonic) into the yarn fiber matrix. References Swatloski, R. P.; Spear, S. K.; Holbrey, J. D.; Rogers, R. D. J. Am Chem Soc, 2002, 124, 4974. Phillips, D. M.; Drummy, L. F.; Conrady, D. G.; Fox, D. M.; Naik, R. R.; Stone, M. O.; Trulove, P. C.; De Long, H. C.; Mantz, R. A. J Am Chem Soc., 2004, 126, 14350. Xie, H.; Zhang, S.; Li, S. Green Chem. , 2006, 8, 630. Haverhals, L. M.; Reichert, W. M.; De Long, H. C.; Trulove, P. C. Cellulose, 2010, 2985, 425. Haverhals, L. M.; Sulpizio, H. M.; Fayos, Z. A.; Trulove, M. A.; Reichert, W. M.; Foley, M. P.; De Long, H. C.; Trulove, P. C.Cellulose, 2012, 19, 13. Haverhals, L. M.; Nevin, L. M.; Foley, M. P.; Brown, E. K.; De Long, H. C.; Trulove, P. C. Chem.Commun., 2012, 48, 6417. Haverhals, L. M.; Brown, E. K.; Foley, M. P.; De Long, H.; Trulove P. ECS Trans, 2012, 50, 603.

In the past decade, ionic liquids (ILs) have been investigated as electrolytes for energy conversion applications such as capacitors [i] ,[ii] , batteries [iii] ,[iv] , fuel cells [v] ,[vi] , and solar cells. [vii] ,[viii] While significant progress has been made towards utilizing these remarkably adaptable materials for specific applications, much work remains to generate technologically and economically relevant devices and processes. Fundamental characterizations of IL-based electrolyte/electrode systems are crucial to continued development for these enterprises. [ix] In specific, detailed descriptions and understanding of electrolyte/electrode interfaces are prerequisites to engineered progress because adsorbed species and their associated interfacial dynamics play critical roles in determining device efficiencies. [x] ,[xi] Our initial studies focus on spectroscopic techniques such as surface enhanced infrared absorption (SEIRA) spectroscopy to characterize interfacial structure and dynamics between ionic liquid media and electrode surfaces during electrochemical perturbation. More specifically, we will discuss characterizations of ILs composed of imidazolium-based cations with alkylsulfate, tetrafluoroborate, thiocyanate, dicyanamide, and bis(trifluoromethylsulfonyl)imide anions at noble metal electrodes (i.e, Au). [i]. T. Sato, G. Masuda, K. Takagi, Electrochim. Acta, 2004, 49, 3603-3611. [ii]. A. Orita, K. Kamijima, M. Yoshida, J. Power Sources, 2010, 195, 7471-7479. [iii]. A. S. Best, A. I. Bhatt, A. F. Hollenkamp, J. Electrochem. Soc., 2010, 157, A903-A911. [iv]. J.-K. Kima, A. Matica, J.-H. Ahnb, P. Jacobsson, J. Power Sources, 2010, 195, 7639-7643. [v]. S.-Y. Lee, A. Ogawa, M. Kanno, H. Nakamoto, T. Yasuda, M. Watanabe, J. Am. Chem. Soc., 2010, 132, 9764-9773. [vi]. M. Guo, J. Fang, H. Xu, W. Li, X. Lu, C. Lan, K. Li, J. Membr. Sci., 2010, 362, 97-104. [vii]. P. K. Singh, N. A. Jadhav, S. K. Mishra, U. P. Singh, B. Bhattacharya, Ionics, 2010, 16, 645-648. [viii]. C.-P. Lee, P.-Y. Chen, R. Vittal, K.-C. Ho, J. Mater. Chem., 2010, 20, 2356-2361. [ix]. C. Aliaga, C. S. Santos, S. Baldelli, Phys. Chem. Chem. Phys., 2007, 9, 3683-3700. [x]. A. J. Bard, L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, 2nd ed., 2002, John Wiley & Sons, Inc., New York, NY. [xi]. M. Yoshida, A. Yamakata, K. Takanabe, J. Kubota, M. Osawa, K. Domen, J. Am. Chem. Soc., 2009, 131, 13218-13219.