An ultrasensitive and highly compressive piezoresistive sensor based on a biopolyol-reinforced polyurethane sponge coated with silver nanoparticles and carbon nanotubes/cellulose nanocrystals

Carey Lea silver hydrosol is a rare example of very concentrated colloidal solutions produced with citrate as only protective ligands, and prospective for a wide range of applications, whose properties have been insufficiently studied up to now. Herein, the reactivity of the immobilized silver nanoparticles toward oxidation, sulfidation, and sintering upon their interaction with hydrogen peroxide, sulfide ions, and chlorocomplexes of Au(III), Pd(II), and Pt(IV) was investigated using SEM and X-ray photoelectron spectroscopy (XPS). The reactions decreased the number of carboxylic groups of the citrate-derived capping and promoted coalescence of 7 nm Ag NPs into about 40 nm ones, excluding the interaction with hydrogen peroxide. The increased nanoparticles form loose submicrometer aggregates in the case of sulfide treatment, raspberry-like micrometer porous particles in the media containing Pd(II) chloride, and densely sintered particles in the reaction with inert H2PtCl6 complexes, probably via the formation of surface Ag-Pt alloys. The exposure of Ag NPs to HAuCl4 solution produced compact Ag films along with nanocrystals of Au metal and minor Ag and AgCl. The results are promising for chemical ambient temperature sintering and rendering silver-based nanomaterials, for example, for flexible electronics, catalysis, and other applications.

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3D-Printable Carbon Nanotubes-Based Composite for Flexible Piezoresistive Sensors

Materials ◽

10.3390/ma13235482 ◽

2020 ◽

Vol 13 (23) ◽

pp. 5482

Author(s):

Chaima Fekiri ◽

Ho Chan Kim ◽

In Hwan Lee

Keyword(s):

Carbon Nanotubes ◽

Flexible Electronics ◽

Applied Pressure ◽

Structural Complexity ◽

High Sensitivity ◽

Cost Effective ◽

Measurement Range ◽

Resistance Change ◽

Piezoresistive Pressure Sensor ◽

Wide Range

The intersection between nanoscience and additive manufacturing technology has resulted in a new field of printable and flexible electronics. This interesting area of research tackles the challenges in the development of novel materials and fabrication techniques towards a wider range and improved design of flexible electronic devices. This work presents the fabrication of a cost-effective and facile flexible piezoresistive pressure sensor using a 3D-printable carbon nanotube-based nanocomposite. The carbon nanotubes used for the development of the material are multi-walled carbon nanotubes (MWCNT) dispersed in polydimethylsiloxane (PDMS) prepolymer. The sensor was fabricated using the direct ink writing (DIW) technique (also referred to as robocasting). The MWCNT-PDMS composite was directly printed onto the polydimethylsiloxane substrate. The sensor response was then examined based on the resistance change to the applied load. The sensor exhibited high sensitivity (6.3 Ω/kPa) over a wide range of applied pressure (up to 1132 kPa); the highest observed measurement range for MWCNT-PDMS composite in previous work was 40 kPa. The formulated MWCNT-PDMS composite was also printed into high-resolution 3-dimensional shapes which maintained their form even after heat treatment process. The possibility to use 3D printing in the fabrication of flexible sensors allows design freedom and flexibility, and structural complexity with wide applications in wearable or implantable electronics for sport, automotive and biomedical fields.

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Preparation of Flexible Electrodes Based on Silver Nanoparticles-Carbon Nanotubes (AgNPs-CNTs) and Elastomer Composites for Soft Electronics

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.18611 ◽

2020 ◽

Vol 20 (9) ◽

pp. 5563-5569

Author(s):

Hanwhuy Lim ◽

Eunkyoung Kim ◽

Baek-Jin Kim

Keyword(s):

Carbon Nanotubes ◽

Silver Nanoparticles ◽

Flexible Electronics ◽

Mechanical Stability ◽

Electrical Circuit ◽

Cycle Duration ◽

Test Machine ◽

Flexible Electrode ◽

Elastomer Composites ◽

Polydimethylsiloxane Elastomer

For flexible electronics devices, a composite of silver nanoparticles-carbon nanotubes (AgNPs-CNTs) and polydimethylsiloxane elastomer were well mixed using a planetary mixer and a 3-roll mill. The ratio of Ag/polymer was varied by adding different size of AgNPs and modified with 12 kinds of flexible electrode compositions. The electrical and mechanical stability of the electrode was measured by combining universal test machine and cyclic voltammetry at once and it showed remarkable stability during 200% strain and 100 cycle duration test. The stable and repeatable electrical circuit was demonstrated while bending and stretching the electrode even higher than 120% strain. Furthermore, the soft gripper incorporating a flexible electrode was fabricated to lift a thin target paper based on electroadhesive force.

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A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins

Nanomaterials ◽

10.3390/nano11051346 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1346

Author(s):

Andreas Breitwieser ◽

Uwe B. Sleytr ◽

Dietmar Pum

Keyword(s):

Carbon Nanotubes ◽

Covalent Modification ◽

Silica Layer ◽

Medical Sciences ◽

Lysinibacillus Sphaericus ◽

Wide Range ◽

Catalytic Sites ◽

Multi Walled Carbon Nanotubes ◽

Pristine Mwnts ◽

Walled Carbon Nanotubes

Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In this context, this work demonstrates the non-covalent modification and dispersion of pristine multi-walled carbon nanotubes (MWNTs) using two S-layer proteins, namely, SbpA from Lysinibacillus sphaericus CCM2177 and SbsB from Geobacillus stearothermophilus PV72/p2. Both the S-layer proteins coated the MWNTs completely. Furthermore, it was shown that SbpA can form caps at the ends of MWNTs. Reassembly experiments involving a mixture of both S-layer proteins in the same solution showed that the MWNTs were primarily coated with SbsB, whereas SbpA formed self-assembled layers. The dispersibility of the pristine nanotubes coated with SbpA was determined by zeta potential measurements (−24.4 +/− 0.6 mV, pH = 7). Finally, the SbpA-coated MWNTs were silicified with tetramethoxysilane (TMOS) using a mild biogenic approach. As expected, the thickness of the silica layer could be controlled by the reaction time and was 6.3 +/− 1.25 nm after 5 min and 25.0 +/− 5.9 nm after 15 min. Since S-layer proteins have already demonstrated their capability to bind (bio)molecules in dense packing or to act as catalytic sites in biomineralization processes, the successful coating of pristine MWNTs has great potential in the development of new materials, such as biosensor architectures.

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Synthesis of silver nanoparticles embedded with single-walled carbon nanotubes for printable elastic electrodes and sensors with high stability

Scientific Reports ◽

10.1038/s41598-021-84386-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jae-Won Lee ◽

Joon Young Cho ◽

Mi Jeong Kim ◽

Jung Hoon Kim ◽

Jong Hwan Park ◽

...

Keyword(s):

Carbon Nanotubes ◽

Silver Nanoparticles ◽

High Performance ◽

Composite Films ◽

Single Walled Carbon Nanotubes ◽

Gauge Factor ◽

Time Interval ◽

Single Walled Carbon ◽

Irradiation Energy ◽

Walled Carbon Nanotubes

AbstractSoft electronic devices that are bendable and stretchable require stretchable electric or electronic components. Nanostructured conducting materials or soft conducting polymers are one of the most promising fillers to achieve high performance and durability. Here, we report silver nanoparticles (AgNPs) embedded with single-walled carbon nanotubes (SWCNTs) synthesized in aqueous solutions at room temperature, using NaBH4 as a reducing agent in the presence of highly oxidized SWCNTs as efficient nucleation agents. Elastic composite films composed of the AgNPs-embedded SWCNTs, Ag flake, and polydimethylsiloxane are irradiated with radiation from a Xenon flash lamp within a time interval of one second for efficient sintering of conductive fillers. Under high irradiation energy, the stretchable electrodes are created with a maximum conductivity of 4,907 S cm−1 and a highly stretchable stability of over 10,000 cycles under a 20% strain. Moreover, under a low irradiation energy, strain sensors with a gauge factor of 76 under a 20% strain and 5.4 under a 5% strain are fabricated. For practical demonstration, the fabricated stretchable electrode and strain sensor are attached to a human finger for detecting the motions of the finger.

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Microstructure, electrical conductivity, and wear behavior of aluminum-carbon nanotubes and biosynthesized silver nanoparticles composites

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-07151-x ◽

2021 ◽

Author(s):

Clifford Ugochukwu Nwoji ◽

Victor Sunday Aigbodion ◽

John Akpan John

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Silver Nanoparticles ◽

Wear Behavior

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A Tough Flexible Cellulose Nanofiber Air Cathode for Oxygen Reduction Reaction with Silver Nanoparticles and Carbon Nanotubes in Rechargeable Zinc-Air Batteries

Energy & Fuels ◽

10.1021/acs.energyfuels.1c00859 ◽

2021 ◽

Author(s):

Shengjuan Li ◽

Wenyi Zhao ◽

Nan Zhang ◽

Yi Luo ◽

Yue Tang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Silver Nanoparticles ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Reduction Reaction ◽

Cellulose Nanofiber ◽

Air Cathode ◽

Zinc Air Batteries

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Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Nanomaterials ◽

10.3390/nano11081875 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1875

Author(s):

Alexander Yu. Gerasimenko ◽

Artem V. Kuksin ◽

Yury P. Shaman ◽

Evgeny P. Kitsyuk ◽

Yulia O. Fedorova ◽

...

Keyword(s):

Carbon Nanotubes ◽

Electrical Conductivity ◽

Laser Irradiation ◽

Flexible Electronics ◽

Threshold Energy ◽

Wavelength Region ◽

Hybrid Nanostructures ◽

Graphene Sheets ◽

Electrically Conductive ◽

Walled Carbon Nanotubes

A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).

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Metal Organic Frameworks Derived Fe-N-C Nanostructures as High-Performance Electrodes for Sodium Ion Batteries and Electromagnetic Interference (EMI) Shielding

Molecules ◽

10.3390/molecules26041018 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1018

Author(s):

Vadahanambi Sridhar ◽

Inwon Lee ◽

Hyun Park

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Electromagnetic Interference ◽

Sodium Ion ◽

Iron Nitride ◽

Sodium Ion Batteries ◽

Nitrogen Doped ◽

Wide Range ◽

Metal Organic ◽

Nitrogen Doped Carbon

Metal organic framework (MOF)-derived carbon nanostructures (MDC) synthesized by either calcinations or carbonization or pyrolysis are emerging as attractive materials for a wide range of applications like batteries, super-capacitors, sensors, water treatment, etc. But the process of transformation of MOFs into MDCs is time-consuming, with reactions requiring inert atmospheres and reaction time typically running into hours. In this manuscript, we report the transformation of 1,4-diazabicyclo[2.2.2]octane, (DABCO)-based MOFs into iron nitride nanoparticles embedded in nitrogen-doped carbon nanotubes by simple, fast and facile microwave pyrolysis. By using graphene oxide and carbon fiber as microwave susceptible surfaces, three-dimensional nitrogen-doped carbon nanotubes vertically grown on reduced graphene oxide (MDNCNT@rGO) and carbon fibers (MDCNT@CF), respectively, were obtained, whose utility as anode material in sodium-ion batteries (MDNCNT@rGO) and for EMI (electromagnetic interference) shielding material (MDCNT@CF) is reported.

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