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Biodegradable polymers have been widely used in tissue engineering with the potential to be replaced by regenerative tissue. While conventional bionic interfaces are designed to be implanted in living tissue and organs permanently, biocompatible and biodegradable electronic materials are now progressing a paradigm shift towards transient and regenerative bionic engineering. For example, biodegradable bioelectronics can monitor physiologies in a body, transiently rehabilitate disease symptoms, and seamlessly form regenerative interfaces from synthetic electronic devices to tissues by reducing inflammatory foreign-body responses. Conventional electronic materials have not readily been considered biodegradable. However, several strategies have been adopted for designing electroactive and biodegradable materials systems: (1) conductive materials blended with biodegradable components, (2) molecularly engineered conjugated polymers with biodegradable moieties, (3) naturally derived conjugated biopolymers, and (4) aqueously dissolvable metals with encapsulating layers. In this review, we endeavor to present the technical bridges from electrically active and biodegradable material systems to edible and biodegradable electronics as well as transient bioelectronics with pre-clinical bio-instrumental applications, including biodegradable sensors, neural and tissue engineering, and intelligent drug delivery systems.

Cellulose nanofibers (CNFs) have received considerable attention as reinforcing fillers due to their excellent and versatile properties, including physical, morphological, and chemical features. Despite many advantages of CNFs, the hydrophilic nature of CNFs significantly limits their use as fillers. In this study, CNFs were modified by esterification with two kinds of carboxylic acids: valeric acid (VA) and hexanoic acid (HA). The degree of substitutions (DS) of VA-CNF and HA-CNF was 2.78 ± 0.04 and 2.61 ± 0.02, respectively. The dispersibility in an isopropanol solvent showed the controlled hydrophilicity of the modified CNFs. Moreover, the water contact angles of VA-CNF and HA-CNF were 79.2 ± 3.1° and 85.0 ± 1.7°, respectively, while the neat CNF was just 18.9 ± 1.6°. The thermogravimetric analysis (TGA) revealed that the modified CNFs have much better thermal stability than the neat CNFs. Also, the CNF films showed uniform-sized nano-porous structures after the modifications of CNFs. Combined with well-improved hydrophobicity, these multi-faceted results suggest that our esterification technique of CNFs can be applied in a wide range of eco-friendly materials applications.

A biosensor was prepared with natural melanin nanoparticles (MNP) decorated on a screen-printed carbon electrode (SPCE). Hexavalent chromium was selected as a well-known heavy metal ion to be detected for testing the performance of novel biosensor. Natural MNP was extracted from cuttlefish (Sepia officinalis) ink. Surface decoration of SPCEs with MNP was performed by two different methods. The first one was layer-by-layer assembly (LBL-A) for different cycle times(n). In the second one, plasma treatment of SPCE incorporated with evaporation-induced self-assembly (EI-SA) techniques including different incubation times in MNP solutions. The performance of both modified SPCEs were tested for amperometric detection of Cr(VI) in various water samples, and peak reduction of Cr(VI) was determined at 0.33 V. Amperometric results showed wide linear ranges of 0.1–2 ?M and 0.1–5 ?M of Cr(VI) for SPCEs modified with 14n-LBL-A and 12h-EI-SA, respectively. The sensitivities of SPCEs modified with 14n-LBL-A and 12h-EI-SA techniques were 0.27 ?A ?M?1 and 0.52 ?A ?M?1, respectively. In addition, both modified SPCEs selectively detected Cr(VI) in a model aqueous system composed of certain other heavy metals and minerals, and tap and lake water samples. The LOD and LOQ values for 12h-EI-SA were 0.03 ?M and 0.1 ?M, respectively. This showed that MNP-modified-SPCEs generated via EI-SA techniques have the potential to be an alternative to conventional detection methods such as ICP-MS.

Micro- and nanotextured surfaces with reconfigurable textures can enable advancements in the control of wetting and heat transfer, directed assembly of complex materials, and reconfigurable optics, among many applications. However, reliable and programmable directional shape in large scale is significant for prescribed applications. Herein, we demonstrate the self-directed fabrication and actuation of large-area elastomer micropillar arrays, using magnetic fields to both program a shape-directed actuation response and rapidly and reversibly actuate the arrays. Specifically, alignment of magnetic microparticles during casting of micropost arrays with hemicylindrical shapes imparts a deterministic anisotropy that can be exploited to achieve the prescribed, large-deformation bending or twisting of the pillars. The actuation coincides with the finite element method, and we demonstrate reversible, noncontact magnetic actuation of arrays of tens of thousands of pillars over hundreds of cycles, with the bending and twisting angles of up to 72 and 61°, respectively. Moreover, we demonstrate the use of the surfaces to control anisotropic liquid spreading and show that the capillary self-assembly of actuated micropost arrays enables highly complex architectures to be fabricated. The present technique could be scaled to indefinite areas using cost-effective materials and casting techniques, and the principle of shape-directed pillar actuation can be applied to other active material systems.

Hybrid nanomaterials possess integrated multi-components to syncretize various properties and functions within a single entity. Owing to this synergistic effect, they promise efficient anti-cancer therapy. In line with this target, we produced stimuli-responsive nanoparticle-nanofiber hybrids (NNHs) via embedding photoresponsive natural melanin nanoparticles (MNPs) within a biocompatible polycaprolactone (PCL) nanofiber matrix. Electrospinning was performed to produce monolithic and core-shell structured NNHs using a single and a coaxial nozzle. The NNHs were upgraded to drug delivery systems by model hydrophilic drug-ampicillin (amp)-loading. The drug release results showed that monolithic PCL meshes displayed a burst release, whereas nanohybrid formation with MNPs improved the release profile toward Fickian diffusion. Core-shell NNH presented a more sustained drug release profile than its MNP-free replica and monolithic NNH because its encapsulating shell layer hindered the diffusion of the drug. The photodynamic therapy accompanied by UV-A-irradiation on monolithic and core-shell NNHs yielded up to 34 % and 37 % malignant melanoma cell death. Moreover, this study proved the potency of MNPs-enhanced NNHs in drug delivery and photodynamic therapy applications. Even so, more efforts should be concerted to unlock unknown features of the NNHs, which have the power to advance emerging areas, including but not limited to material science, biosensing, and theranostics.

Inspired by nature, we fabricated optically tuned bio-organic films of cellulose nanofibers (CNFs) and chitosan by precisely structuring layer-by-layer (LBL) assembly techniques. Directly extracted from tunicate, highly crystalline CNFs were deposited into gradual nanoporous structures, which dictates wave-like behaviors of optical transmittance and cyclic patterns of structural coloration. The optical transmittance of a glass substrate increased from 91% to 98.2% at a wavelength of 550 nm by reflectivity attenuation controls. The monochromic structural colors were discretely varied from orange to purple, seen only at a specific angle of the incident light, demonstrating visibly hidden security potential. Furthermore, we could modulate the coloration cycles by accelerating the LBL processes with polydopamine-coated CNFs. The 3D nanoporous structures of CNFs also provide synergies, including superhydophilic surface-driven antifogging properties. Our optically versatile biofilms made by all-natural CNFs and chitosan provide various potential applications, including solar cells, securities, and eco-friendly colors.

Pine wilt disease caused by Bursaphelenchus xylophilus is a major tree disease that threatens pine forests worldwide. To diagnose this disease, we developed battery-powered remote sensing devices capable of long-range (LoRa) communication and installed them in pine trees (Pinus densiflora) in Gyeongju and Ulsan, South Korea. Upon analyzing the collected tree sensing signals, which represented stem resistance, we found that the mean absolute deviation (MAD) of the sensing signals was useful for distinguishing between uninfected and infected trees. The MAD of infected trees was greater than that of uninfected trees from August of the year, and in the two-dimensional plane, consisting of the MAD value in July and that in October, the infected and uninfected trees were separated by the first-order boundary line generated using linear discriminant analysis. It was also observed that wood moisture content and precipitation affected MAD. This is the first study to diagnose pine wilt disease using remote sensors attached to trees.

Voice is one of the essential mechanisms for communicating and expressing one’s intentions as a human being. There are several causes of voice inability, including disease, accident, vocal abuse, medical surgery, ageing, and environmental pollution, and the risk of voice loss continues to increase. Novel approaches should have been developed for speech recognition and production because that would seriously undermine the quality of life and sometimes leads to isolation from society. In this review, we survey mouth interface technologies which are mouth-mounted devices for speech recognition, production, and volitional control, and the corresponding research to develop artificial mouth technologies based on various sensors, including electromyography (EMG), electroencephalography (EEG), electropalatography (EPG), electromagnetic articulography (EMA), permanent magnet articulography (PMA), gyros, images and 3-axial magnetic sensors, especially with deep learning techniques. We especially research various deep learning technologies related to voice recognition, including visual speech recognition, silent speech interface, and analyze its flow, and systematize them into a taxonomy. Finally, we discuss methods to solve the communication problems of people with disabilities in speaking and future research with respect to deep learning components.

In this study, we designed near-infrared (NIR)-responsive Mn2+-doped melanin-like poly(L-DOPA) nanoparticles (MNPs), which act as multifunctional nano-platforms for cancer therapy. MNPs, exhibited favorable π-π stacking, drug loading, dual stimuli (NIR and glutathione) responsive drug release, photothermal and photodynamic therapeutic activities, and T1-positive contrast for magnetic resonance imaging (MRI). First, MNPs were fabricated via KMnO4 oxidation, where the embedded Mn2+ acted as a T1-weighted contrast agent. MNPs were then modified using a photosensitizer, Pheophorbide A, via a reducible disulfide linker for glutathione-responsive intracellular release, and then loaded with doxorubicin through π-π stacking and hydrogen bonding. The therapeutic potential of MNPs was further explored via targeted design. MNPs were conjugated with folic acid (FA) and loaded with SN38, thereby demonstrating their ability to bind to different anti-cancer drugs and their potential as a versatile platform, integrating targeted cancer therapy and MRI-guided photothermal and chemotherapeutic therapy. The multimodal therapeutic functions of MNPs were investigated in terms of T1-MR contrast phantom study, photothermal and photodynamic activity, stimuli-responsive drug release, enhanced cellular uptake, and in vivo tumor ablation studies.

Conductive polymers (CPs) are gaining considerable attention as materials for implantable bioelectronics due to their unique features such as electronic-ionic hybrid conductivity, mechanical softness, ease of chemical modification, as well as moderate biocompatibility. CPs have been utilized for a wide range of applications including neural engineering, regenerative medicine, multi-functional sensors and actuators. This review focuses on CP materials design for use in bio-interfacing electronics including composites, conductive hydrogels, and electrochemical deposition. We start by elaborating on the fundamental materials characteristics of CPs, including bio-electrochemical charge-transfer mechanisms, and contrast them with naturally derived CPs. We then present recent critical examples of the bioelectronic and biomedical applications of CPs, including neural recording and stimulation, tissue regeneration, stretchable electronics, and mechanical actuation. We conclude with a perspective of the current material challenges of CPs in bio-interfacing electronics.

Achieving biological softness and flexibility has been a critical challenge for bio-electronic materials in areas of implantable bionic interfaces and wearable devices. Unlike inherently rigid electronic materials, bioengineered interfaces or scaffolds require stretchable softness as well as functional porosity for selective ionic transports. Toward this goal of providing electrically conducting biomaterials, we report ultrathin single-walled carbon nanotube (SWNT) layer coating on biodegradable polycaprolactone (PCL) membranes via layer-by-layer (LBL) assembly technique. The resulting membranes have unique, hierarchically structured 3D network of conductive paths around asymmetric nano-/micro-pores, providing softness as well as stretchable, anisotropic electrical conductivity. The strain sensors embedded on the membrane also demonstrate bending directional sensitivity as well as piezoresistivity with tunable Gauge Factor (GF) in the ranges of 5–13 with stretchability of up to 100%. Furthermore, these composite membranes are biocompatible as evident by neuronal cell attachment tests with in vitro PC12 cell lines. As follows, this newly developed implantable multifunctional membrane has considerable potential for applications in bioengineered devices such as mechano-sensitive artificial interfaces and skins.

Thylakoids, on which complete sets of photosynthetic membrane proteins are contained, behave as soft nanoparticles of a few tens nm sizes. Thus, we separated the thylakoid extracts from spinach chloroplasts and densely organized them in a film with either insulating polyethyleneimine (PEI) or conducting polyaniline (PANI) by molecularly controlled layer-by-layer (LBL) assembly. The resulting nanostructured composite films demonstrated photoelectrochemical activities with thylakoids whose stabilities were significantly improved on the charge balanced LBL multilayers compared to one on a randomly deposited film or in solution. The thylakoid LBL films continuously generated photochemical electrons for longer than 130 h with the 2,6-dichlorophenolindophenol (DCPIP) mediated photosynthetic energy conversion cycle while photoactivities of thylakoid moiety slowly decreased in the open circuit potential measurements throughout which the photosynthetic redox cycles were incomplete. As the photofunctional groups of the thylakoid films originated from a biotic system and the photofuctional thylakoids were exceptionally well preserved on the charge-balanced artificial structures, the developed thylakoid LBL film have shown inherent biocompatibility upon PC12 neural cell attachment and differentiation tests, which are essential qualities for emerging human-friendly electronic applications such as disposable electronics, artificial retina, and implantable neural interfacing meditronics as well as cell-free photosynthetic production.

In this study, polyethylene glycol (PEG) conjugated melanin nanoparticles (MNPs) were prepared (PEG-MNPs). A model chemotherapy drug, doxorubicin (DOX), was loaded into the PEG-MNPs with varied concentrations (0.125, 0.250, 0.500 mg/mL). TEM images showed that, DOX-PEG-MNPs are spherical-shaped and 15 ± 2.2 nm in diameter. FTIR spectroscopy analysis demonstrated that MNPs were successfully modified with PEG. The UV–Vis spectroscopy results showed that the drug loading capacity of MNPs was 0.7 mg/ml of DOX in 2 mg/ml of PEG-MNPs. The time course data showed that, the release behavior of DOX from MNPs was primarily diffusion controlled. In vitro cytotoxicity assays demonstrated that MNP and PEG-MNP did not show any toxic effect on mouse fibroblast cells while DOX-PEG-MNP was able to inhibit the proliferation of human breast cancer cells. The results confirm that the application area of MNPs in controlled and prolonged drug release could be extended to the different types of cancer therapeutics.

Nanocellulose has emerged for a wide range of applications in biomedical engineering because of its water absorption capacity, appropriate elasticity. We investigated the hemostatic and regenerative abilities of an expanding polyvinyl alcohol (PVA)-nanocellulose sponge on nasal mucosal defects. A 3 mm-diameter nasal defect was made in experimental rabbits. Rabbits were divided into four groups with control, vaseline, PVA and PVA-nanocellulose packing groups. After the defect was created, bleeding times and amounts were monitored. Packing materials were removed on experimental day (ED) 2. On ED 3, 7 and 14, histological analysis and immunohistochemical study for neutrophils were performed. Inflammatory cells were counted and epithelial thicknesses were evaluated. Bleeding amounts and times in the vaseline packing group were smaller than in the PVA groups. PVA-nanocellulose group showed less neutrophils than in the other groups on ED 7. Average epithelium thickness in the PVA-nanocellulose group was significantly smaller than in the control group at ED 7, but at ED 14, there was no significant intergroup difference. PVA-nanocellulose group had a significant lower inflammatory cell count than the control group on ED 7. PVA-nanocellulose sponge applied to nasal mucosal defects can significantly enhance mucosal regeneration during early wound healing.

The microporous layer (MPL) in proton exchange membrane fuel cells (PEMFCs) improves the fuel cell performance remarkably. However, PEMFCs suffer from local oxygen starvation at high current densities because of the accumulation of water at the cathode. This paper presents a novel water management technique that uses open furrows with serpentine patterns in the MPL. The laser ablation technique is used to carve open furrows in the MPL, and the various properties of the furrowed MPL are characterized. To examine the effects of the furrowed MPL on water management, the polarization behavior, impedance response, and potential variation under dynamic load tests are studied experimentally and theoretically for PEMFCs with three different gas diffusion layers. The results indicate that open furrows in the MPL reduce the water saturation in the catalyst layer and increase the water discharge to the gas flow channel, thereby promoting oxygen transport to the catalyst sites.

We describe the synthesis and characterization of hierarchically porous organic-inorganic hybrid silica with periodic 2-D hexagonal order and tunable location of secondary nanopores through co-condensation of tetraethylorthosilicate (TEOS) and a new type of amphiphilic organosilicate precursors. Our amphiphilic organosilicates offer unique tunability of secondary micropores by carefully controlled bond molecular structure and number of bonds between hydrophobic adamantylphenols pore-generating moieties and siloxane precursors. Small angle X-ray scattering (SAXS) and microscopy results show a good structural order of the organic-inorganic hybrid silica. In addition, 29Si CP-MAS NMR spectra confirm the successful incorporation of organosilicate precursors into a silica framework. The primary cylindrical mesopores (∼6.4 nm) were originated from the cooperative self-assembly of Pluronic P123 triblock copolymer templates while smaller meso-/micropores were derived from adamantylphenols groups. We have previously demonstrated that adam-graft SQ had an affinity for hydrophobic PO core blocks to be located close to PO segment, which resulted in small pores next to primary mesopores and the resultant increment of mesopore size as well as wrinkled silica walls. On the contrary, the secondary small pores were mainly generated within a silica network while the size of the primary mesopores unaffected with the addition of adam-bridge SQ due to its selective incorporation into a silica framework. Moreover, the organic-inorganic hybrid silica prepared with adam-bridge SQ showed higher thermal stability than that of adam-graft SQ and SBA-15 type mesoporous silica. It is attributed to more Si O Si bonds formed from the bridged structure as well as enhanced hydrogen-bonding interaction between adam-bridge SQ hybrid silica and P123 templates.

Melanin is a common name used for a certain type of natural dark pigments existing in living organisms, particularly in human hair, eyes, and skin. The unique free radical scavenging effect of melanine could help protecting cells and tissues from harmful UV light. While their exact molecular structures in nature are not still well defined, their multifunctional properties including electrical and ionic conductivities, antioxidation, wet adhesion, and metal ion chelation, are highlighted for the potential applications in bioorganic electronics including biomedical sensors and devices. In this mini-review, we will discuss sources, synthesis methods, structures and multifunctional properties of melanin materials in addition to current research directions on a wide range of applications.

This study investigates how academics hired during the period of rapid neoliberal reforms differ from the senior academics hired before the reforms and the junior academics hired after the reforms were institutionalized. The faculty members who were employed in a period of radical reform may be impacted by the additional requirements and tasks caused by the reforms while they are also expected to do more traditional duties. They could be regarded as the ‘sandwich generation’ and may be suffering from overloaded. Through the survey data and interview data of this article, however, the authors found that the younger generation (the ‘new generation’) is overloaded, and their job stress is higher than either old generation (the ‘academic boomers’) or the sandwich generation. Although the new generation has a stronger preference for research than other generations, they spend less time on research and more time on administration than the others. Accordingly, the new generation is highly stressed. In addition, ...

Cellulose, the chain of glucose residues easily obtained from nature, is the most common natural polymer. Owing to its own unique material properties, compared to the conventional usage, nanocellulose (NC) with a crystalline structure can be considered to be used in various industrial applications. As a novel sustainable future material, we review the recent achievements of NC from the view point of material extraction and the composite processes to some extended important applications. While the mechanical properties of NCs and the energy consumption during their composite processing are the key considerations, their application potentials have never been limited to mechanical or commodity products as conventional celluloses. In the latter part of this review, emerging engineering applications of NCs such as energy storage, flexible electronics, and smart materials will be further discussed for readers searching future high-end eco-friendly functional materials. Also some suggestions for potential applications will be also discussed.

현대사회에서 우리는 스트레스에 둘러싸여 자연과 단절된 삶을 살아가고 있으며 이는 여러 질환의 발병원인이 되고 있다. 또한 과거에 비하여 정신건강문제 경험자 수와 정신의료기관 입원환자의 수도 증가하였다. 이에 본연구는 산림체험 프로그램이 정신과 입원환자의 기분상태와 우울 및 스트레스정도에 미치는 영향을 알아보기 위하여 수행하였다. 나주시 N병원의 정신과에 입원 중인 실험군 12명과 대조군 13명을 대상으로 2013년 5월 20일부터29일까지 5회에 걸쳐 산림체험 프로그램이 실시되었으며, 기분상태 검사지(K-POMS-B)와 Beck 우울검사지(BDI) 및타액을 활용하여 그 효과를 검증하였다. 연구결과, 산림체험 프로그램에 참여한 환자의 경우 우울상태가 호전되고 스트레스가 감소되었으며, 스트레스 감소효과는 통계적으로 유의하였다(p

We describe the synthesis and characterization of bicontinuous cubic poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer gels prepared within lyotropic cubic poly(oxyethylene)10 nonylphenol ether (NP-10) templates with Ia3[combining macron]d (gyroid, GYR) symmetry. The chemical polymerization of EDOT monomer in the hydrophobic channels of the NP-10 GYR phase was initiated by AgNO3, a mild oxidant that is activated when exposed to ultraviolet (UV) radiation. The morphology and physical properties of the resulting PEDOT gels were examined as a function of temperature and frequency using optical and electron microscopy, small-angle X-ray scattering (SAXS), dynamic mechanical spectroscopy, and electrochemical impedance spectroscopy (EIS). Microscopy and SAXS results showed that the PEDOT gels remained ordered and stable after the UV-initiated chemical polymerization, confirming the successful templated-synthesis of PEDOT in bicontinuous GYR nanostructures. In comparison to unpolymerized 3,4-ethylenedioxythiophene (EDOT) gel phases, the PEDOT structures had a higher storage modulus, presumably due to the formation of semi-rigid PEDOT-rich nanochannels. Additionally, the storage modulus (G') for PEDOT gels decreased only modestly with increasing temperature, from ∼1.2 × 10(5) Pa (10 °C) to ∼7 × 10(4) Pa (40 °C), whereas G' for the NP-10 and EDOT gels decreased dramatically, from ∼5.0 × 10(4) Pa (10 °C) to ∼1.5 × 10(2) Pa (40 °C). EIS revealed that the impedance of the PEDOT gels was smaller than the impedance of EDOT gels at both high frequencies (PEDOT ∼10(2) Ω and EDOT 2-3 × 10(4) Ω at 10(5) Hz) and low frequencies (PEDOT 10(3)-10(5) Ω and EDOT ∼5 × 10(5) Ω at 10(-1) Hz). These results indicated that PEDOT gels were highly ordered, mechanically stable and electrically conductive, and thus should be of interest for applications for which such properties are important, including low impedance and compliant coatings for biomedical electrodes.

The real-time temperature measurement of nanostructured materials is particularly attractive in view of increasing needs of local temperature probing with high sensitivity and resolution in nanoelectronics, integrated photonics, and biomedicine. Light-induced heating and Raman scattering of single-walled carbon nanotubes with adsorbed gold nanoparticles decorating silica microparticles are reported, by both green and near IR lasers. The plasmonic shell is used as nanoheater, while the single-walled carbon nanotubes are Raman active and serve as a thermometer. Stokes and Anti-Stokes Raman spectra of single-walled carbon nanotubes serve to estimate the effective light-induced temperature rise on the metal nanoparticles. The temperature rise is constant with time, indicating stability of the adsorption density. The effective temperatures derived from Stokes and Anti-Stokes intensities are correlated with those measured in a heating stage. The resolution of the thermal experiments in our study was found to be 5-40 K.

Graphene, a carbon crystal sheet of molecular thickness, shows diverse and exceptional properties ranging from electrical and thermal conductivities, to optical and mechanical qualities. Thus, its potential applications include not only physicochemical materials but also extends to biological uses. Here, we review recent experimental studies about graphene for such bioapplications. As a prerequisite to the search to determine the potential of gra- phene for bioapplications, the essential qualities of graphene that support biocompatibility, were briefly summarized. Then, direct examples of tissue regeneration and tissue engineer - ing utilizing graphenes, were discussed, including uses for cell scaffolds, cell modulating interfaces, drug delivery, and neural interfaces.

Gold nanoparticle aggregate carbone nanotube functionalized colloidal particles serve as probes for label-free stable detection of biomolecules inside living cells. The probes provide the means of effective localization of signal and produce significant enhancement of Raman scattering of molecules. The approach demonstrated in this work opens opportunities for detection and imaging of biomolecules in cell biology and molecular sensing.

SAN/ nanofibers were fabricated by an electrospinning process and used as chemiresistors for sensing alcohol vapours. A hydrophobic and air-stable ionic liquid, , was used to impart electrical conductivity to insulating SAN nanofibers. The effects of addition on the morphology of the nanofibers were explained in terms of surface tension, viscosity and conductivity. After exposing the SAN/ nanofibers collected on an interdigitated electrode to alcohol vapours (ethanol, 1-propanol and 1-butanol), the resistance of the nanofibers decreased due to adsorption of alcohol molecules. The electrospun SAN/ nanofibers sensor exhibited good sensitivity and reproducibility.

Single-walled carbon nanotube (SWNT) and other carbon-based coatings are being considered as replacements for indium tin oxide (ITO). The problems of transparent conductors (TCs) coatings from SWNT and similar materials include poor mechanical properties, high roughness, low temperature resilience, and fast loss of conductivity. The simultaneous realization of these desirable characteristics can be achieved using high structural control of layer-by-layer (LBL) deposition, which is demonstrated by the assembly of hydroethyl cellulose (HOCS) and sulfonated polyetheretherketone (SPEEK)-SWNTs. A new type of SWNT doping based on electron transfer from valence bands of nanotubes to unoccupied levels of SPEEK through π-π interactions was identified for this system. It leads to a conductivity of 1.1 × 10(5) S/m at 66 wt % loadings of SWNT. This is better than other polymer/SWNT composites and translates into surface conductivity of 920 Ω/◻ and transmittance of 86.7% at 550 nm. The prepared LBL films also revealed unusually high temperature resilience up to 500 °C, and low roughness of 3.5 nm (ITO glass -2.4 nm). Tensile modulus, ultimate strength, and toughness of such coatings are 13 ± 2 GPa, 366 ± 35 MPa, and 8 ± 3 kJ/m(3), respectively, and exceed corresponding parameters of all similar TCs. The cumulative figure of merit, ∏(TC), which included the critical failure strain relevant for flexible electronics, was ∏(TC) = 0.022 and should be compared to ∏(TC) = 0.006 for commercial ITO. Further optimization is possible using stratified nanoscale coatings and improved doping from the macromolecular LBL components.

Single-wall carbon nanotubes modifi ed by anionic polyelectrolyte molecules are embedded into the shells of microcapsules. Carbon nanotubes serve as rigid rods in a softer polymeric capsule, which forms a free-standing shell upon treatment with glutaraldehyde and subsequent drying. The embedded carbon nanotubes exhibit a broad absorption in the UV‐near-infrared part of the spectrum, and that allows point-wise activation and opening of the microcapsules by laser. Raman signal analysis shows changes of carbon-nanotube-specifi c lines after high-power laser irradiation, which is characteristic of the formation of disordered carbonlike structures. These polyelectrolyte/carbon nanotube composite capsules represent a novel light-addressable type of microcontainers.

We present a conformal and lightweight antenna technology based on E-textile conductors and polymer-ceramic composites. Unique advantages of the proposed technology are its structural integrity, light weight and conformity to the platform. E-textile conductors are fabricated with single wall carbon nanotube (SWNT) and Ag coated textiles. They demonstrate good structural integrity with polymer composites due to their mechanical compatibility. Similarly, polymer composites demonstrate superior RF performance with permittivity ranging from 3 to 13. Fabrication process for E-textile conductors and integration process with polymer composites is described in detail. We also demonstrated merit of the proposed technology with a simple patch antenna whose radiation performance is measured when it was flat and conformed onto a cylindrical surface. We compared its performance with that of an ideal patch. Experiments suggested that the sample patch antenna based on the proposed technique achieved 6 dB gain, which is 2 dB below a patch which has the same dimensions and made of ideal lossless materials. When it is conformed onto a cylindrical surface, we achieved 2.5 dB less gain than that of antenna realized with a PEC surface. This clearly validates the merit of the proposed conformal antenna technique based on non-traditional materials.

This review article focuses on the preparation and applications of layer-by-layer (LBL) assembled organic/inorganic films. As model systems we use incorporation of two multi-functional nanomaterials in the LBL: the clay nanosheets and carbon nanotubes. All the aspects of the composite design starting with the structure of the individual nano-scale building blocks and their interactions with polymer matrix, orientation of the inorganic components in the multilayer, origin of record properties, and most likely applications of the resulting materials are given. Special attention is placed on the understanding of the control parameters for key functional properties such as mechanical strength/stiffness/toughness, electrical transport, transparency, and some properties relevant for biological applications.

Exponentially growing layer-by-layer (e-LBL) assembled films attracts a lot of attention mostly due to multiple practical applications in biology and medicine. However, e-LBL was observed only for a very limited number of polymers. This fact inevitably limits the area of research and functionalities that one can obtain for them. Also, it is fundamentally important to gain better understanding of the effect and importance of molecular flexibility for e-LBL films. Here we report that dispersions of rod-like nanocolloids such as single walled carbon nanotubes (SWNTs) and nanowires (NWs) can spontaneously “bore into” and stay in the e-LBL matrix. Molecular rigidity and surface charge appear to be the key parameters determining the possibility of such a process and its extent. SWNT forms a thick 2−25 μm penetration layer, while insufficient flexibility leads to hedgehog structures in the case of CdTe and Te NWs. Electrical properties of the films obtained display fundamental differences with SWNT composites ma...