To improve the interlaminar shear strength (ILSS) of carbon fiber reinforced epoxy composite, networks of multiwalled carbon nanotubes (MWNTs) were grown on micron-sized carbon fibers and single-walled carbon nanotubes (SWNTs) were dispersed into the epoxy matrix so that these two types of carbon nanotubes entangle at the carbon fiber (CF)/epoxy matrix interface. The MWNTs on the CF fiber (CF-MWNTs) were grown by chemical vapor deposition (CVD), while the single-walled carbon nanotubes (SWNTs) were finely dispersed in the epoxy matrix precursor with the aid of a dispersing agent polyimide-graft-bisphenol A diglyceryl acrylate (PI-BDA) copolymer. Using vacuum assisted resin transfer molding, the SWNT-laden epoxy matrix precursor was forced into intimate contact with the "hairy" surface of the CF-MWNT fiber. The tube density and the average tube length of the MWNT layer on CF was controlled by the CVD growth time. The ILSS of the CF-MWNT/epoxy resin composite was examined using the short beam shear test. With addition of MWNTs onto the CF surface as well as SWNTs into the epoxy matrix, the ILSS of CF/epoxy resin composite was 47.59 ± 2.26 MPa, which represented a ∼103% increase compared with the composite made with pristine CF and pristine epoxy matrix (without any SWNT filler). FESEM established that the enhanced composite did not fail at the CF/epoxy matrix interface.

Inkjet printing technology has been extensively studied for depositing thin fi lms of diverse materials for scalable, lowcost printable fl exible electronics. Inkjet printing of carbon nanotube thin fi lm transistors (CN-TFTs) on fl exible or plastic substrate has hitherto achieved relatively poor device performance, or has used uncommon materials as the dielectric. In this paper we report superior performance inkjet printed CN-TFTs using a common dielectric on fl exible substrate. On indium-tin-oxide-coated polyester fi lm, we deposited a thin ( ∼ 70 nm) fi lm of the commonly used stable and high dielectric constant (k) material Hafnium oxide (HfO 2 ) as gate dielectric. After patterning of Au electrodes, active channels were formed by inkjet printing of highly purifi ed (99%) semiconducting carbon nanotube (CN) ink. The resulting CN-TFTs have performance that is superior to other reported fl exible TFTs. We systemically studied the effect of areal density of carbon nanotubes in the active channel (controlled by the amount of printing) and channel length (L C ) on the TFT on-current density, effective mobility, on/off ratio, threshold voltage and gate hysteresis. The optimized inkjet printed CN-TFTs with L C = 160 μ m and channel width (W C ) = 60 μ m exhibit outstanding effective mobility of 43 cm 2 V − 1 s − 1 with on/off ratio ≥ 10 4 , threshold voltage of 4.1 V and gate hysteresis of 2.2 V. Our transistor performance is superior to other reported values using inkjet printing of CNs and common stable microelectronics materials. These demonstrated high-performance inkjet printed CN-TFTs are ready for scalable printable fl exible electronics in the near future.Inkjet printing technology is favored in electronics manufacturing for a wide variety of applications such as organic thin fi lm transistors, [1][2][3] light-emitting diodes, [ 4 , 5 ] solar cells, [6][7][8] memory devices, [ 9 ] and sensors [10][11][12] owing to its reduced material wastage, low cost and scalability to large area manufacturing. The most signifi cant advantage of inkjet printing is that it is a non-contact direct patterning method suitable for depositing diverse materials at precisely controlled position without the use of pre-patterned masks. It has been extensively used as a research tool for exploring various aspects of printed electronics and for realizing applications of novel materials, designs and systems at laboratory scale. Initial research efforts on inkjet printed fl exible electronics have been focused on organic semiconductors, [13][14][15][16][17] owing to their compatibility with plastic substrate and their carrier mobility being comparable to that of amorphous silicon. In recent years, inorganic nanowires and carbon nanotubes have emerged as competitors of organic semiconductors as the active material for electronic devices. [18][19][20][21] Single-walled carbon nanotubes (SWCNTs) are regarded as a potential semiconductor material for printed fl exible electronics but as-synthesized SWCNTs are mixtures containing metallic...

Single-walled carbon nanotube (SWNT) is expected to be a very promising material for flexible and transparent driver circuits for active matrix organic light emitting diode (AM OLED) displays due to its high field-effect mobility, excellent current carrying capacity, optical transparency and mechanical flexibility. Although there have been several publications about SWNT driver circuits, none of them have shown static and dynamic images with the AM OLED displays. Here we report on the first successful chemical vapor deposition (CVD)-grown SWNT network thin film transistor (TFT) driver circuits for static and dynamic AM OLED displays with 6 × 6 pixels. The high device mobility of ~45 cm2V−1s−1 and the high channel current on/off ratio of ~105 of the SWNT-TFTs fully guarantee the control capability to the OLED pixels. Our results suggest that SWNT-TFTs are promising backplane building blocks for future OLED displays.

Active food packaging materials that are sustainable, biodegradable, and capable of precise delivery of antimicrobial active ingredients (AIs) are in high demand. Here, we report the development of novel enzyme- and relative humidity (RH)-responsive antimicrobial fibers with an average diameter of 225 ± 50 nm, which can be deposited as a functional layer for packaging materials. Cellulose nanocrystals (CNCs), zein (protein), and starch were electrospun to form multistimuli-responsive fibers that incorporated a cocktail of both free nature-derived antimicrobials such as thyme oil, citric acid, and nisin and cyclodextrin-inclusion complexes (CD-ICs) of thyme oil, sorbic acid, and nisin. The multistimuli-responsive fibers were designed to release the free AIs and CD-ICs of AIs in response to enzyme and RH triggers, respectively. Enzyme-responsive release of free AIs is achieved due to the degradation of selected polymers, forming the backbone of the fibers. For instance, protease enzyme can degrade zein polymer, further accelerating the release of AIs from the fibers. Similarly, RH-responsive release is obtained due to the unique chemical nature of CD-ICs, enabling the release of AIs from the cavity at high RH. The successful synthesis of CD-ICs of AIs and incorporation of antimicrobials in the structure of the multistimuli-responsive fibers were confirmed by X-ray diffraction and Fourier transform infrared spectrometry. Fibers were capable of releasing free AIs when triggered by microorganism-exudated enzymes in a dose-dependent manner and releasing CD-IC form of AIs in response to high relative humidity (95% RH). With 24 h of exposure, stimuli-responsive fibers significantly reduced the populations of foodborne pathogenic bacterial surrogates Escherichia coli (by ∼5 log unit) and Listeria innocua (by ∼5 log unit), as well as fungi Aspergillus fumigatus (by >1 log unit). More importantly, the fibers released more AIs at 95% RH than at 50% RH, which resulted in a higher population reduction of E. coli at 95% RH. Such biodegradable, nontoxic, and multistimuli-responsive antimicrobial fibers have great potential for broad applications as active and smart packaging systems.

There is a great need for viable alternatives to today’s transparent conductive film using largely indium tin oxide. We report the fabrication of a new type of flexible transparent conductive film using silver nanowires (AgNW) and single-walled carbon nanotube (SWCNT) networks which are fully embedded in a UV curable resin substrate. The hybrid SWCNTs-AgNWs film is relatively flat so that the RMS roughness of the top surface of the film is 3 nm. Addition of SWCNTs networks make the film resistance uniform; without SWCNTs, sheet resistance of the surface composed of just AgNWs in resin varies from 20 Ω/sq to 107 Ω/sq. With addition of SWCNTs embedded in the resin, sheet resistance of the hybrid film is 29 ± 5 Ω/sq and uniform across the 47 mm diameter film discs; further, the optimized film has 85% transparency. Our lamination-transfer UV process doesn’t need solvent for sacrificial substrate removal and leads to good mechanical interlocking of the nano-material networks. Additionally, electrochemical study of the film for supercapacitors application showed an impressive 10 times higher current in cyclic voltammograms compared to the control without SWCNTs. Our fabrication method is simple, cost effective and enables the large-scale fabrication of flat and flexible transparent conductive films.