Poly(ionic liquid)-based ionogels are excellent all-poly(electrolyte) candidates for electroactive actuation applications, but investigation of their actuation behavior and ionogel properties has largely been limited to styrenic block copolymers. In this work, ionogels were prepared from a novel poly(ionic liquid) (PIL) block copolymer, poly[(2-dimethyl amino)ethyl methacrylate)]-block-poly[4-vinylbenzyl-3-butyl imidazolium bis(trifluoromethylsulfonyl)imide] (PDMAEMA-b-PVBBImTf(2)N) combined with an ionic liquid, 1-butyl-3-methyl imidazolium tetrafluoroborate (C(4)C(1)ImBF(4)), at weight percentages between 0 to 40 wt%. Under a low applied voltage (4 V DC) microscale actuation was achieved for films prepared from the neat PDMAEMA-b-PVBBImTf(2)N block copolymer, as well as its corresponding 10 wt% ionogel; this result critically expands the PIL block copolymer chemistries available for electroactive actuator applications. Thermal, ionic conductivity, morphology, and mechanical modulus properties of the PDMAEMA-b-PVBBImTf(2)N ionogels were also assessed to evaluate their potential for electrochemical applications. Addition of the ionic liquid to form an ionogel significantly increased the thermal stability of the PDMAEMA polymer block and successfully plasticized the PDMAEMA-b-PVBBImTf(2)N block copolymer ionogel, as evidenced by decreases in the glass transition temperature and significant enhancement of the ionic conductivity from similar to 10(-7) S/cm in the neat polymers to similar to 10(-4) S/cm in the 40 wt% ionogels. AFM force curve analyses using a Derjaguin-Muller-Toporov (DMT) model showed a reduction of Young's modulus for the block copolymer matrix as a function of increasing ionic liquid content, and the PDMAEMA-rich phase exhibits a higher modulus, which serves to mechanically reinforce the PIL matrix. In combination the material properties and electrical responsiveness of these novel all-polyelectrolyte PDMAEMA-b-PVBBImTf(2)N block copolymer ionogels show excellent potential for micro-scale electroactive actuation and other electrochemical applications.

Gels of semiconducting polymers have many potential applications, including biomedical devices and sensors. Here, we report a self-assembled gel system consisting of isoindigo-based semiconducting polymers with galactose side chains in benign, alcohol-based solvents. Because of the carbohydrate side chains, the modified isoindigo polymers are soluble in alcohols. We obtained thermoreversible gels in 1-propanol using these polymers and di-Fmoc-l-lysine, a molecular gelator. The polymers and molecular gelators have been selected in such a way that they do not have significant physical interactions. The molecular gelator self-assembled to form a fibrous structure that confines the polymer chains in the interstitial spaces of the fibers. The polymer chains formed local aggregations and increased the shear moduli of the gels significantly. Bulky galactose side chains and the less planar nature of the polymer backbone hindered the formation of long-range assembled structures of the polymers. However, the dispersion of polymers throughout the gel samples resulted in a percolated structure in the dried gel films. The bulk electrical conductivity of dried gels confirmed the presence of such percolated structures. Our results demonstrated that carbohydrate-containing conjugated polymers can be combined with molecular gelators to obtain gels in eco-friendly solvents.

Lignin@Fe3O4 nanoparticles adsorb at oil-water interfaces, form Pickering emulsions, induce on-demand magnetic responses to break emulsions, and can sequester oil from water. Lignin@Fe3O4 nanoparticles were prepared using a pH-induced precipitation method and were fully characterized. These were used to prepare Pickering emulsions with castor oil/Sudan red G dye and water at various oil/water volume ratios and nanoparticle concentrations. The stability and demulsification of the emulsions under different magnetic fields generated with permanent magnets (0-540 mT) were investigated using microscopy images and by visual inspection over time. The results showed that the Pickering emulsions were more stable at the castor oil/water ratio of 50/50 and above. Increasing the concentration of lignin@Fe3O4 improved the emulsion stability and demulsification rates with 540 mT applied magnetic field strength. The adsorption of lignin@Fe3O4 nanoparticles at the oil/water interface using 1-pentanol evaporation through Marangoni effects was demonstrated, and magnetic manipulation of a lignin@Fe3O4 stabilized castor oil spill in water was shown. Nanoparticle concentration and applied magnetic field strengths were analyzed for the recovery of spilled oil from water; it was observed that increasing the magnetic strength increased oil spill motion for a lignin@Fe3O4 concentration of up to 0.8 mg mL-1 at 540 mT. Overall, this study demonstrates the potential of lignin-magnetite nanocomposites for rapid on-demand magnetic responses to externally induced stimuli.

Polyaniline (PANI) is one of the most accessible conducting polymers and is known for its environmental stability in its partially oxidized conductive state. However, it is difficult to process and undergoes electrochemical degradation between its partially and fully oxidized states. While there have been several approaches to address PANI's processability, little has been done to address its electrochemical instability. We have prepared two polyaniline derivatives that contain a phenoxazine unit copolymerized with 2,5-dimethyl-p-phenylenediamine (P1) and p-phenylenediamine (P2) and determined their optoelectronic properties, processability, morphology, and electrochemical stability. Camphor sulfonic acid (CSA) doped polymers were dissolved in organic solvents and cast into films, which were analyzed by absorption spectroscopy, cyclic voltammetry, and conductivity measurements. Importantly, the films exhibit outstanding electrochemical stability over multiple redox and spectroelectrochemical cycles and conductivity in the high semiconductive regime (0.1 to 1 S/cm) when exposed to m-cresol vapors. Additionally, P1 exists as aggregates in the absence of m-cresol vapors, but as highly conductive sheet-like structures in the presence of m-cresol as shown by SEM, TEM, and AFM images. These results show that P1 and P2 would be outstanding candidates for applications that required stable redox conductive polymers.

The capacity for microscopic evaluation of sperm is useful for assisted reproductive technologies (ART), because this can allow for specific selection of sperm cells for in vitro fertilization (IVF). The objective of this study was to analyze the same sperm samples using two high-resolution methods: spatial light interference microscopy (SLIM) and atomic force microscopy (AFM) to determine if with one method there was more timely and different information obtained than the other. To address this objective, there was evaluation of sperm populations from boars and stallions. To the best of our knowledge, this is the first reported comparison when using AFM and high-sensitivity interferometric microscopy (such as SLIM) to evaluate spermatozoa. Results indicate that with the use of SLIM microscopy there is similar nanoscale sensitivity as with use of AFM while there is approximately 1,000 times greater throughput with use of SLIM. With SLIM, there is also allowace for the measurement of the dry mass (non-aqueous content) of spermatozoa, which may be a new label-free marker for sperm viability. In the second part of this study, there was analysis of two sperm populations. There were interesting correlations between the different compartments of the sperm and the dry mass in both boars and stallions. Furthermore, there was a correlation between the dry mass of the sperm head and the length and width of the acrosome in both boars and stallions. This correlation is positive in boars while it is negative in stallions.

We report the preparation of carbon-based nanomaterials from biopolymer kraft lignin via an iron catalytic thermal treatment process. Both the carbonaceous gases and amorphous carbon (AC) from lignin thermal decomposition were found to have participated in the formation of graphitic-carbon-encapsulated iron nanoparticles (GCEINs). GCEINs originating from carbonaceous gases have thick-walled graphitic-carbon layers (10 to 50) and form at a temperature of 700 °C. By contrast, GCEINs from AC usually have thin-walled graphitic-carbon layers (1 to 3) and form at a temperature of at least 800 °C. Iron catalyst nanoparticles started their phase transition from α-Fe to γ-Fe at 700 °C, and then from γ-Fe to Fe3C at 1000 °C. Furthermore, we derived a formula to calculate the maximum number of graphitic-carbon layers formed on iron nanoparticles via the AC dissolution-precipitation mechanism.

Co-polymer systems of methylene diphenyl diisocyanate (MDI) and phenol-formaldehyde (PF) resins with different molecular weights were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The FTIR and TGA coupled with differential thermogravimetric (DTG) results showed that higher molecular weight of PF resins not only promoted the reaction of isocyanate and PF co-polymer system, but also resulted in a better thermal property of prepared co-polymers. The XRD results revealed that higher molecular weight led to a higher proportion of ordered or crosslinking structures in the hybrid resin system. The relationship between the thermal resistance, mechanical properties and the molecular weights of phenolic resins needs further study.

Journal Article Direct Conversion Biogas to Multiwall Carbon Nanotubes and Syngas over Starch Derived Ni@C Nanoparticles Get access Qiangu Yan, Qiangu Yan Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS, USA Search for other works by this author on: Oxford Academic Google Scholar Fei Yu, Fei Yu Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS, USA Search for other works by this author on: Oxford Academic Google Scholar I-Wei Chu, I-Wei Chu Institute for Imaging and Analytical Technologies, Mississippi State University, Mississippi State, MS, USA Search for other works by this author on: Oxford Academic Google Scholar Amanda Lawrence Amanda Lawrence Institute for Imaging and Analytical Technologies, Mississippi State University, Mississippi State, MS, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 1829–1830, https://doi.org/10.1017/S1431927615009927 Published: 23 September 2015

ABSTRACTThe aim of this work was to enhance poly(lactic acid)'s (PLA) flexibility and ductility by blending it with another bioplastic. Poly(trimethylene malonate) (PTM), developed as part of this study, was synthesized from 1,3‐propane diol and malonic acid via melt polycondensation. Blend films of PLA and PTM were prepared by solvent casting from chloroform. Differential scanning calorimetry and thermogravimetric analysis were used to show shifted phase transitions and a single glass‐transition temperature, indicating miscibility of PTM in the blend films. Morphology and mechanical characterizations of the PLA/PTM blend films were performed by atomic force microscopy using a quantitative nanomechanical property mapping mode, tensile testing, and scanning electron microscopy. Miscible blends exhibited Young's modulus and elongation at break values that can significantly extend the usefulness of PLA in commercial applications. The blending of PTM with PLA resulted in films with a 27‐fold increase in toughness compared with neat PLA film. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40888.

Utilizing the inherent negative charge of mica surfaces, amine-functionalized magnetic nanoparticles (Fe3O4/NH2) were electrostatically adsorbed onto the mica such that surface-initiated ATRP could be used to grow poly(n-isopropylacrylamide) (PNIPAM) from the exposed hemisphere. By reducing the solution pH, a positive charge generated on the mica was used to release the nanoparticles from the substrate. A second ATRP reaction was carried out to grow poly(methacrylic acid) (PMAA) from the initiated surfaces. As a result, the Fe3O4/NH2 core has a polymer shell with one hemisphere PMAA and the other hemisphere PNIPAM-b-PMAA resulting in the PMAA-Fe3O4-PNIPAM-b-PMAA bicompartmental polymer Janus nanoparticles. Elemental and functional group compositions were confirmed using ATR-FTIR, XPS, and EDS. Imaging with AFM, SEM, and TEM showed the evolution of the Janus nanoparticle morphology. This study demonstrates a facile and innovative scheme involving a noncovalent solid protection technique combined with sequential, surface-confined controlled radical polymerizations for the production of multicomponent nanocomposites.

Nanoparticle self-assembly is fundamentally important for bottom-up functional device fabrication. Currently, most nanoparticle self-assembly has been achieved with gold nanoparticles (AuNPs) functionalized with surfactants, polymeric materials, or cross-linkers. Reported herein is a facile synthesis of gold and silver nanoparticle (AgNP) films assembled onto thiophene oil by simply vortex mixing neat thiophene with colloidal AuNPs or AgNPs for ∼1 min. The AuNP film can be made using every type of colloidal AuNPs we have explored, including sodium borohydride-reduced AuNPs with a diameter of ∼5 nm, tannic acid-reduced AuNPs of ∼10 nm diameter, and citrate-reduced AuNPs with particle sizes of ∼13 and ∼30 nm diameter. The AuNP film has excellent stability and it is extremely flexible. It can be stretched, shrunken, and deformed accordingly by changing the volume or shape of the enclosed thiophene oil. However, the AgNP film is unstable, and it can be rapidly discolored and disintegrated into small flakes that float on the thiophene surface. The AuNP and AgNP films prepared in the glass vials can be readily transferred to glass slides and metal substrates for surface-enhanced Raman spectral acquisition.

Organothiol (R-SH) (OT) adsorption onto silver nanoparticles (AgNPs) in water was studied for a series of aromatic OTs including p-methylbenzenethiol (p-MBT), p-benzenedithiol (p-BDT), and 2-mercaptobenzimidazole (2-MBI). Unlike the common view that OT forms monolayer adsorption on AgNPs, we found that these aromatic OTs continuously reacted with AgNPs through formation of RS-Ag complexes until complete OT or AgNP consumption occurred. The RS-Ag complex can remain on the AgNP surface, converting the AgNPs into core-shell structures. The OT adsorption onto AgNPs occurs predominately through reaction with silver oxide present on the AgNP surfaces before the OT addition or formed from environmental oxygen in the presence of OT. The RS-H protons are completely released when both p-MBT and 2-MBI reacted with AgNP, Ag2O, and AgNO3. However, a substantial fraction of S-H bonds remained intact when p-BDT, the only dithiol used in this work, is adsorbed on AgNPs or reacted independently with Ag2O and AgNO3. The new insights from this work should be important for understanding OT interaction with AgNPs in water and the SERS spectra of the OT adsorbed onto AgNPs.

Determination of the true surface areas, concentrations, and particle sizes of gold nanoparticles (AuNPs) is a challenging issue due to the nanoparticle morphological irregularity, surface roughness, and size distributions. A ligand adsorption-based technique for determining AuNP surface areas in solution is reported. Using a water-soluble, stable, and highly UV-vis active organothiol, 2-mercaptobenzimidazole (MBI), as the probe ligand, we demonstrated that the amount of ligand adsorbed is proportional to the AuNP surface area. The equivalent spherical AuNP sizes and concentrations were determined by combining the MBI adsorption measurement with Au(3+) quantification of aqua regia-digested AuNPs. The experimental results from the MBI adsorption method for a series of commercial colloidal AuNPs with nominal diameters of 10, 30, 50, and 90 nm were compared with those determined using dynamic light scattering, transmission electron microscopy, and localized surface plasmonic resonance methods. The ligand adsorption-based technique is highly reproducible and simple to implement. It only requires a UV-vis spectrophotometer for characterization of in-house-prepared AuNPs.

Verfahren zur Herstellung eines multiferroischen Dunnschichtmaterials. Das Verfahren enthalt die Schritte der Bereitung einer Mulitferroikum-Vorstufenlosung, das Schleudergiesen dieser Vorstufenlosung zur Herstellung einer Schleuderguss-Dunnschicht und das Erhitzen dieser Schleuderguss-Dunnschicht. Die Vorstufenlosung kann Bi(NO3)3·5H2O und Fe(NO3)3·9H2O in Ethylenglykol enthalten, um eine Wismutferrit-Dunnschicht herzustellen. Auserdem kann diese Dunnschicht auf verschiedenen technologischen Gebieten eingesetzt werden, wozu Speichervorrichtungen zur Speicherung von Informationen gehoren.

Multiferroics represent a class of new materials having potential applications for design and preparation of multifunctional material due to the possibility of the coupling of their coexisting electric and magnetic orderings. The magnetic polarization can be switched by applying an electric field; and the electric polarization, by applying a magnetic field. We report here our attempts using three approaches for fabricating multiferroic ferrites: autoclave, microemulsion and spin-casting. All three methods are based on a precursor solution prepared by dissolving stoichiometric amount of bismuth(III) nitrate and iron(III) nitrate in ethylene glycol. In the autoclave synthesis, sodium hydroxide and hydrogen peroxide were dissolved in DI water with surfactant (Triton x-100, Tx-100) and then the precursor solution was added. The solution was transferred to an autoclave at either 165 or 185 °C for reaction for 24 hours. The two temperatures led to two different bismuth ferrite nanocrystals, Bi 2 Fe 4 O 9 (165 °C) and BiFeO 3 (185 °C). For microemulsion synthesis, sodium hydroxide and hydrogen peroxide were dissolved in DI water and added to an oil solution (cyclohexane and n-butanol) with added surfactant, Tx-100, as “Emulsion I”. “Emulsion II” was made by adding precursor in an oil solution (cyclohexane and n-butanol). “Emulsion I” was allowed to react with “emulsion II” at 80 °C for 3 hours. A non-crystalline bismuth ferrite with a 1:1 atomic ratio for Bi∶ Fe was obtained. The spin-casting method produced the BiFeO 3 (BFO) thin film with the desired quality. The quality of the resulting BFO thin film depended strongly on the spinning rates and annealing temperatures. The morphology of all samples was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). X-ray dispersive spectroscopy (EDS) was used to confirm the elemental composition in bismuth ferrite samples. X-ray diffraction (XRD) was used for establishing crystalline structures.

Single crystalline nanoneedles of three families of the most studied conductive organic polymers - polythiophene, polyaniline and polypyrrole - were synthesized for the first time using an interfacial polymerization process that takes place with simultaneous crystallization. As the crystal growth is concurrent with polymerization, more ordered crystal packing can be expected. Most of the bulk conducting-polymer systems studied contains regions that are inhomogeneous. Single nanocrystals of conducting polymers have not been reported, although needle-shaped bulk crystals of the quarterphenyl cation radical salt have previously been studied. The investigation of processes in a nanodomain of a single crystal is critical in ascertaining the inherent electronic properties of polymer nanoelements. The organic conductive nanoneedles were characterized using TEM, HRTEM, electron diffraction, EDS, and EPR to establish their crystal structure and composition. Scanning tunneling microscopy/spectroscopy (STM/STS) investigation were conducted to examine their electronic behaviors, leading to the discovery of a field-induced conductance switching with response times on the millisecond level. The switch voltages are in the range of 3 to 4 volts in STM experiments, consistent with the trend of the band gap of the three polymers. The organic conductive nanoneedles with nano-tip having high density of mobile electron may serve as interesting elements for nanoscale electronics.