An ultrasensitive and low-cost graphene sensor based on layer-by-layer nano self-assembly

Flexible wearable strain sensors with excellent sensing performance have received widespread interest due to their superior application capability in the field of human-computer interaction, sports rehabilitation, and disease diagnosis. But at present, it is still a considerable challenge to exploit a flexible strain sensor with high sensitivity and wide sensing range that is easily manufactured, low-cost, and easily integrable into clothing. MXene is a promising material sensitive enough for flexible sensors due to its superior conductivity and hydrophilicity. The warp knitting weft insertion textile structure gives the fabric excellent elasticity, making it suitable as a flexible, stretchable substrate. Therefore, utilizing a polyester elastic fabric with a warp knitting weft insertion structure, a fabric strain sensor with high sensitivity and wide sensing range prepared by layer-by-layer self-assembly of polyvinyl alcohol layers and MXene layers is reported in this study. The strain sensor exhibits high sensitivity (up to 288.43), a wide sensing range (up to 50%), fast response time (50 ms), ultra-low detection limit (a strain of 0.067%), excellent cycle stability (1000 cycles), and good washability. Besides, affixing the MXene/polyvinyl alcohol/polyester elastic fabric strain sensor on the joints can detect the movement of limbs. Therefore, the MXene/polyvinyl alcohol/polyester elastic fabric strain sensor demonstrates potential application opportunities in smart wearable electronic devices, and the researcher can also apply this method in the production of other flexible, intelligent wearable devices.

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Single-Walled Carbon Nanotube Micropatterns and Interconnections Fabricated With Layer-by-Layer Nano Self-Assembly and Microlithography on Flexible Substrates

CANEUS2006: MNT for Aerospace Applications ◽

10.1115/caneus2006-11054 ◽

2006 ◽

Author(s):

Wei Xue ◽

Tianhong Cui

Keyword(s):

Carbon Nanotube ◽

Self Assembly ◽

Low Cost ◽

Flexible Substrates ◽

Layer By Layer ◽

Single Walled Carbon Nanotube ◽

Plastic Substrates ◽

Single Walled Carbon ◽

Current Voltage ◽

Lift Off

The fabrication and characterization of single-walled carbon nanotube (SWNT) multilayers, micropatterns and interconnections on plastic substrates are reported in this paper. The SWNT-based multilayers and devices are fabricated with a simple, fast, inexpensive, low-temperature, and highly efficient technique combining layer-by-layer (LbL) nano self-assembly, microlithography, and lift-off techniques. The SWNT multilayers are alternating layers of SWNTs and poly (dimethyldiallylammonium chloride) (PDDA). Lithography and lift-off techniques are used to pattern the SWNT multilayers. SWNT microstructures with linewidth of 5 μm are fabricated and characterized. The thickness of a (PDDA/SWNT) bi-layer is approximately 76 Å. Two-terminal SWNT thin film based interconnections are fabricated on flexible substrates. Current-voltage (I-V) characterization and four-point probe measurement show that the resistance of the interconnection is nonlinearly inversely proportional to the number of the assembled SWNT layers. The nano-assembled polymer/SWNT composite can be used in many applications due to its low cost, light weight, and long lifetime.

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Flexible Layer-by-Layer Self-Assembled Graphene Based Glucose Biosensors

Volume 11: Nano and Micro Materials, Devices and Systems; Microsystems Integration ◽

10.1115/imece2011-64423 ◽

2011 ◽

Author(s):

Bo Zhang ◽

Tony Zhengyu Cui

Keyword(s):

Self Assembly ◽

Low Cost ◽

Glucose Biosensor ◽

Layer By Layer ◽

Glucose Biosensors ◽

Flexible Polymer ◽

Assembly Technique ◽

Self Assembled ◽

The Cost

The manufacture and characterization of glucose biosensor based on layer by layer self assembled graphene are presented. Due to self assembly technique and flexible polymer substrate, the cost of the biosensor is very competitive. The resolution of the graphene based biosensor reaches down to 10 pM, which shows greater advantages over CNT based biosensor under the same conditions. The response time of graphene biosensor is less than 3 s, which is much faster than other materials and methods. This work demonstrates that graphene and polymers are very promising materials for the applications of low-cost glucose biosensors.

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Layer-by-Layer Fabrication of Hydrogel Microsystems for Controlled Drug Delivery From Untethered Microrobots

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.692648 ◽

2021 ◽

Vol 9 ◽

Author(s):

Roberto Bernasconi ◽

Fabio Pizzetti ◽

Arianna Rossetti ◽

Brendan Butler ◽

Marinella Levi ◽

...

Keyword(s):

Drug Delivery ◽

Smart Materials ◽

Self Assembly ◽

Low Cost ◽

Active Material ◽

Burst Release ◽

Layer By Layer ◽

Poor Control ◽

Major Interest

Targeted drug delivery from untethered microrobots is a topic of major interest in current biomedical research. The possibility to load smart materials able to administer active principles on remotely in vivo guidable microdevices constitutes one of the most attractive opportunities to overcome the drawbacks of classical untargeted delivery methodologies. Hydrogels, in particular, are ideal candidates as drug-carrying materials due to their biocompatibility, low cost, and ease of manufacturing. On the other hand, these polymers suffer from poor control over release rate and overall released amount. Starting from these premises, the present article demonstrates the possibility to tune the release of hydrogels applied on magnetically steerable microrobots by fabricating microsystems via layer-by-layer self-assembly. By doing this, the diffusion of chemicals from the hydrogel layers to the external environment can be optimized and the phenomenon of burst release can be strongly limited. The microrobotic platforms employed to transport the hydrogel active material are fabricated by employing 3D printing in combination with wet metallization and present a gold layer on their surface to enhance biocompatibility. The maneuverability of microdevices coated with both thin and thick multilayers is investigated, individuating optimized parameters for efficient actuation.

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Solution-Based Fabrication of P-Channel and N-Channel Thin-Film Transistors Using Random and Aligned Carbon Nanotube Networks

Volume 9: Micro- and Nano-Systems Engineering and Packaging, Parts A and B ◽

10.1115/imece2012-86353 ◽

2012 ◽

Author(s):

Yan Duan ◽

Jason L. Juhala ◽

Benjamin W. Griffith ◽

Vianney J. Uwizeye ◽

Wei Xue

Keyword(s):

Integrated Circuits ◽

Self Assembly ◽

Control Method ◽

Field Effect Transistors ◽

Low Cost ◽

Logic Gates ◽

Special Treatment ◽

Layer By Layer ◽

Research Fields ◽

P Type

Since discovered in the early 1990s, single-walled carbon nanotubes (SWNTs) have attracted significant attention for many research fields. In the long term, micro- and nano-electronics are considered to be one of the most valuable applications of SWNTs. The development of the next generation devices involves the mass fabrication and integration of SWNT field-effect transistors (FETs) to form logic gates, which are the basic units of integrated circuits (ICs). To create logic gates, both p- and n-type SWNT FETs are needed. However, the SWNT FETs are typically p-type in air without special treatment, with holes as the majority charge carriers in SWNTs. Here in this paper, we investigate the p-channel and n-channel SWNT FETs using two solution-based fabrication processes. One method is to use layer-by-layer self-assembly to create SWNT random networks and the other is based on dielectrophoresis-aligned SWNTs. A low-cost, easy-to-control method is introduced to convert p-type FETs to n-type. By coating a polyethylenimine (PEI) layer on the surface, the transistor demonstrates the typical n-channel characteristics. The resulting devices are air-stable outside a vacuum or an inert environment. The combination of the simple fabrication methods, easy conversion of the devices, and satisfactory device performance can promote further development of nanotube-based electronics.

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Plant-Inspired Layer-by-Layer Self-Assembly of Super-Hydrophobic Coating for Oil Spill Cleanup

Polymers ◽

10.3390/polym11122047 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2047 ◽

Cited By ~ 2

Author(s):

Liping Ding ◽

Yanqing Wang ◽

Jinxin Xiong ◽

Huiying Lu ◽

Mingjian Zeng ◽

...

Keyword(s):

Oil Spill ◽

Self Assembly ◽

Low Cost ◽

Layer By Layer ◽

Water Mixture ◽

Hydrophobic Coating ◽

Molecular Building Block ◽

Modification Method ◽

Oil Water ◽

Oil Spill Cleanup

A versatile, facile, energy-saving, low-cost and plant-inspired self-assembly strategy was used to prepare super-hydrophobic coating in this study. Concretely, an appealing super-hydrophobicity surface was obtained by designing a molecular building block phytic acid (PA)-Fe (III) complex to anchor the substrate and hydrophobic thiol groups (HT). The facile and green modification method can be applied to variety of substrates. The as-prepared PA-Fe (III)–HT coated melamine composite sponge possesses both super-hydrophobic and superlipophilicity property. Moreover, it displays superior efficiency to separate the oil–water mixture and splendid oil spill cleanup.

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Construction of Antifouling Membrane Surfaces through Layer-by-Layer Self-Assembly of Lignosulfonate and Polyethyleneimine

Polymers ◽

10.3390/polym11111782 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1782 ◽

Cited By ~ 4

Author(s):

Lin Gu ◽

Meng-Yun Xie ◽

Yu Jin ◽

Min He ◽

Xiao-Yan Xing ◽

...

Keyword(s):

Self Assembly ◽

Low Cost ◽

Membrane Surface ◽

Value Added ◽

Layer By Layer ◽

Natural Polymer ◽

Water Contact ◽

Membrane Surfaces ◽

Cost Strategy ◽

Low Cost Strategy

Lignin is the second most abundant and low-cost natural polymer, but its high value-added utilization is still lack of effective and economic ways. In this paper, waste lignosulfonate (LS) was introduced to fabricate antifouling membrane surfaces via layer-by-layer self-assembly with polyethyleneimine (PEI). The LS/PEI multilayers were successfully deposited on the polysulfone (PSf) membrane, as demonstrated by ATR-FTIR, XPS, Zeta potential measurements, AFM, and SEM. Meanwhile, the effect of the number of bilayers was investigated in detail on the composition, morphologies, hydrophilicity, and antifouling performance of the membrane surface. As a result, with the bilayer numbers increase to 5, the PSf membrane shows smooth surface with small roughness, and its water contact angle reduces to 44.1°, indicating the improved hydrophilicity. Accordingly, the modified PSf membrane with 5 LS/PEI bilayers repels the adsorption of protein, resulting in good antifouling performance. This work provides a green, facile, and low-cost strategy to construct antifouling membrane surfaces.

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A High-Resolution Amperometric Acetylcholine Sensor Based on Nano-Assembled Carbon Nanotube and Acetylcholinesterase Thin Films

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.1.1 ◽

2008 ◽

Vol 1 ◽

pp. 1-9 ◽

Cited By ~ 16

Author(s):

Wei Xue ◽

Tianhong Cui

Keyword(s):

Carbon Nanotubes ◽

Carbon Nanotube ◽

High Resolution ◽

Self Assembly ◽

Low Cost ◽

Fast Response ◽

Time Measurement ◽

Layer By Layer ◽

Real Time Measurement ◽

Assembly Technique

We demonstrate a carbon nanotube based high-resolution biosensor for acetylcholine sensing. Carbon nanotubes are deposited on a silicon wafer in a repeated fashion with layer-by-layer nano self-assembly technique. With nano-assembled acetylcholinesterase molecules on the surface, the carbon nanotube biosensor is capable of detecting acetylcholine at an ultra-low concentration of 100 pM. The sensitivity of the acetylcholine sensor is measured as 7.2 µA/decade. The real-time measurement shows the response time of the biosensor is approximately 6 sec. Both the carbon nanotube film and the acetylcholinesterase film are crucial in the sensing process. Due to its high resolution, fast response, small size, and low cost, the carbon nanotube biosensor has tremendous potential for applications in medical research and clinical diagnosis.

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