Microscale 3D Printed Patterns for Nanoscale Particle Assembly

2021 ◽  
Author(s):  
Sayli Jambhulkar ◽  
Weiheng Xu ◽  
Yuxiang Zhu ◽  
Dharneedar Ravichandran ◽  
Kenan Song
Keyword(s):  
Close Packing ◽  
Gauge Factor ◽  
Contact Lines ◽  
Particle Assembly ◽  
Sensing Applications ◽  
3D Printed ◽  
Assembly Procedure ◽  
Printed Patterns ◽  
Solid Liquid ◽  
Shed Light

Abstract Directed particle assembly has broad applications in sensors, actuators, microelectronics, robotics, and the biomedical area. Currently available methods include external fields such as electrical or magnetic fields, surface treatment on substrates, and DNA-assisted templates. However, these methods are most efficient at the nanoscale and would lose their efficiency and scalability above microscales. We reported in this research the uses of the 3D printed surface to direct the assembly of nanoparticles. We used carbon nanofibers (CNFs) as an example to show the long-range orders after dipping the 3D printed substrates in CNFs suspensions. The anchoring of CNFs at the solid-liquid-air contact lines will initiate the assembly procedure and further induced the neighboring CNFs because of the van der Waals forces. As a result, the CNFs formed well-regulated bands with controlled spacing and close-packing. These assembled CNFs were demonstrated in sensing applications. A gauge factor regulated the methanol at different concentrations and temperatures to pass the sensor, with the device resistivity change. In this way, the sensitivity as a function of analyte concentration and temperatures was obtained. This research studied nanoparticles’ microscale assembly based on a simple 3D printing surface and shed light on a new hybrid manufacturing for nanoparticle assembly.

Optimization of 3D Printed Elastomeric Nanocomposites for Flexible Strain Sensing Applications

2019 ◽  
Author(s):  
Mohammad Abshirini ◽  
Mohammad Charara ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan ◽  
Yingtao Liu
Keyword(s):  
3D Printing ◽  
Strain Sensor ◽  
Sensitive Strain ◽  
Curing Temperature ◽  
Gauge Factor ◽  
Strain Sensing ◽  
Sensing Applications ◽  
Wide Range ◽  
Load Rate ◽  
3D Printed

Abstract Flexible and sensitive strain sensors can be utilized as wearable sensors and electronic devices in a wide range of applications, such as personal health monitoring, sports performance, and electronic skin. This paper presents the fabrication of a highly flexible and sensitive strain sensor by 3D printing an electrically conductive polydimethylsiloxane (PDMS)/multi-wall carbon nanotube (MWNT) nanocomposite on a PDMS substrate. To maximize the sensor’s gauge factor, the effects of MWNT concentration on the strain sensing function in nanocomposites are evaluated. Critical 3D printing and curing parameters, such as 3D printing nozzle diameter and nanocomposites curing temperature, are explored to achieve the highest piezoresistive response, showing that utilizing a smaller deposition nozzle size and higher curing temperature can result in a higher gauge factor. The optimized 3D printed nanocomposite sensor’s sensitivity is characterized under cyclic tensile loads at different maximum strains and loading rates. A linear piezoresistive response is observed up to 70% strain with an average gauge factor of 12, pointing to the sensor’s potential as a flexible strain sensor. In addition, the sensing function is almost independent of the applied load rate. The fabricated sensors are attached to a glove and used as a wearable sensor by detecting human finger and wrist motion. The results indicate that this 3D printed functional nanocomposite shows promise in a broad range of applications, including wearable and skin mounted sensors.

scholarly journals Anisotropic, Wrinkled, and Crack-Bridging Structure for Ultrasensitive, Highly Selective Multidirectional Strain Sensors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Heng Zhang ◽  
Dan Liu ◽  
Jeng-Hun Lee ◽  
Haomin Chen ◽  
Eunyoung Kim ◽  
...  
Keyword(s):  
Rational Design ◽  
Full Range ◽  
Human Motion ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Wearable Electronics ◽  
Trade Off ◽  
Human Motion Detection ◽  
Sensing Applications ◽  
Anisotropic Structures

AbstractFlexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications. Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities, existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity. Here, an ultrasensitive, highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers. The bilayer sensor consists of an aligned carbon nanotube (CNT) array assembled on top of a periodically wrinkled and cracked CNT–graphene oxide film. The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched, leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100% strain. The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3, to the benefit of accurate detection of loading directions by the multidirectional sensor. This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity, selectivity, and stretchability, demonstrating promising applications in full-range, multi-axis human motion detection for wearable electronics and smart robotics.

Algorithm to Reduce Leading and Lagging in Conformal Direct-Print

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Morteza Vatani ◽  
Faez Alkadi ◽  
Jae-Won Choi
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
3D Model ◽  
Three Dimensional ◽  
Motion Direction ◽  
B Spline ◽  
And Topology ◽  
Printing System ◽  
3D Printed ◽  
Printed Patterns

A novel additive manufacturing algorithm was developed to increase the consistency of three-dimensional (3D) printed curvilinear or conformal patterns on freeform surfaces. The algorithm dynamically and locally compensates the nozzle location with respect to the pattern geometry, motion direction, and topology of the substrate to minimize lagging or leading during conformal printing. The printing algorithm was implemented in an existing 3D printing system that consists of an extrusion-based dispensing module and an XYZ-stage. A dispensing head is fixed on a Z-axis and moves vertically, while the substrate is installed on an XY-stage and moves in the x–y plane. The printing algorithm approximates the printed pattern using nonuniform rational B-spline (NURBS) curves translated directly from a 3D model. Results showed that the proposed printing algorithm increases the consistency in the width of the printed patterns. It is envisioned that the proposed algorithm can facilitate nonplanar 3D printing using common and commercially available Cartesian-type 3D printing systems.

PLA conductive filament for 3D printed smart sensing applications

2018 ◽  
Vol 24 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Simone Luigi Marasso ◽  
Matteo Cocuzza ◽  
Valentina Bertana ◽  
Francesco Perrucci ◽  
Alessio Tommasi ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Low Cost ◽  
Conductive Polymer ◽  
Temperature Characteristic ◽  
Temperature Sensors ◽  
Electrical Performance ◽  
Content Type ◽  
Sensing Applications ◽  
3D Printed

Purpose This paper aims to present a study on a commercial conductive polylactic acid (PLA) filament and its potential application in a three-dimensional (3D) printed smart cap embedding a resistive temperature sensor made of this material. The final aim of this study is to add a fundamental block to the electrical characterization of printed conductive polymers, which are promising to mimic the electrical performance of metals and semiconductors. The studied PLA filament demonstrates not only to be suitable for a simple 3D printed concept but also to show peculiar characteristics that can be exploited to fabricate freeform low-cost temperature sensors. Design/methodology/approach The first part is focused on the conductive properties of the PLA filament and its temperature dependency. After obtaining a resistance temperature characteristic of this material, the same was used to fabricate a part of a 3D printed smart cap. Findings An approach to the characterization of the 3D printed conductive polymer has been presented. The major results are related to the definition of resistance vs temperature characteristic of the material. This model was then exploited to design a temperature sensor embedded in a 3D printed smart cap. Practical implications This study demonstrates that commercial conductive PLA filaments can be suitable materials for 3D printed low-cost temperature sensors or constitutive parts of a 3D printed smart object. Originality/value The paper clearly demonstrates that a new generation of 3D printed smart objects can already be obtained using low-cost commercial materials.

Flexible Strain Sensor Using Additive Manufacturing and Conductive Liquid Metal: Design, Fabrication, and Characterization

2018 ◽  
Author(s):  
Austin Smith ◽  
Hamzeh Bardaweel
Keyword(s):  
3D Printing ◽  
Liquid Metal ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Limiting Factor ◽  
Successful Implementation ◽  
Conductive Liquid ◽  
Fused Deposition ◽  
3D Printed ◽  
Flexible Strain Sensor

In this work a flexible strain sensor is fabricated using Fused Deposition Modeling (FDM) 3D printing technique. The strain sensor is fabricated using commercially available flexible Thermoplastic Polyurethane (TPU) filaments and liquid metal Galinstan Ga 68.5% In 21% Sn 10%. The strain sensor consists of U-shape 2.34mm long and 0.2mm deep channels embedded inside a TPU 3D printed structure. The performance of the strain sensor is measured experimentally. Gauge Factor is estimated by measuring change in electric resistance when the sensor is subject to 13.2% – 38.6% strain. Upon straining and unstraining, results from characterization tests show high linearity in the range of 13.2% to 38.6% strain with very little hysteresis. However, changes due to permanent deformations are a limiting factor in the usefulness of these sensors because these changes limit the consistency of the device. FDM 3D printing shows promise as a method for fabricating flexible strain sensors. However, more investigation is needed to look at the effects of geometries and 3D printing process parameters on the yield elongation of the flexible filaments. Additionally, more investigation is needed to observe the effect of distorted dimensions of the 3D printed channels on the sensitivity of the strain sensor. It is anticipated that successful implementation of these commercially available filaments and FDM 3D printers will lead to reduction in cost and complexity of developing these flexible sensors.

scholarly journals The Potential of Graphene Nanoplatelets in the Development of Smart and Multifunctional Ecocomposites

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2189
Author(s):  
Pedro Pereira ◽  
Diana P. Ferreira ◽  
Joana C. Araújo ◽  
Armando Ferreira ◽  
Raul Fangueiro
Keyword(s):  
Electrical Conductivity ◽  
Polyethylene Glycol ◽  
Electrical Properties ◽  
Smart Materials ◽  
Textile Composites ◽  
Graphene Nanoplatelets ◽  
Gauge Factor ◽  
Sensing Applications ◽  
Ultraviolet Protection ◽  
Natural Fabrics

Graphene and its derivatives have shown outstanding potential in many fields and textile/composites industry are not an exception. Giving their extraordinary properties, Graphene Nanoplatelets (GNPs) are excellent candidates for providing new functionalities to fibers and composites. In this work, natural fabrics (flax) were functionalized with chitosan (CS) based polymeric formulations of GNPs to develop fibrous systems with electrical properties as well as other functionalities. One of the greatest disadvantages of using carbon-based materials for fabrics’ impregnation is their difficult dispersion. Therefore, several polymers were used as matrices, binding and dispersive agents including chitosan, polyethylene glycol (PEG), and glycerol. All the systems were characterized using several techniques that demonstrated the presence and incorporation of the GNPs onto the composites. Besides their characterization, considering their use as smart materials for monitoring and sensing applications, electrical properties were also evaluated. The highest value obtained for electrical conductivity was 0.04 S m−1 using 2% of GNPs. Furthermore, piezoresistive behavior was observed with Gauge Factor (GF) of 1.89 using 0.5% GNPs. Additionally, UV (ultraviolet) protection ability and hydrophobicity were analyzed, confirming the multifunctional behavior of the developed systems extending their potential of application in several areas.

Study the precision of fixed partial dentures of Co-Cr alloys cast over 3D printed prototypes

2018 ◽  
Vol 1 (90) ◽  
pp. 25-32 ◽  
Author(s):  
Ts. Dikova ◽  
Dzh. Dzhendov ◽  
Iv. Katreva ◽  
Ts. Tonchev
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Dimensional Accuracy ◽  
Average Roughness ◽  
Dental Clinics ◽  
Primary Model ◽  
3D Printers ◽  
3D Printed ◽  
The Right ◽  
Printed Patterns

Purpose: of this paper is to investigate the accuracy of Co-Cr dental bridges, manufactured using 3D printed cast patterns. Design/methodology/approach: Four-unit dental bridges are fabricated from the alloys i-Alloy and Biosil-f by lost-wax process. The polymeric cast patterns are 3D printed with different layer’s thickness (13 μm, 35 μm and 50 μm). Two 3D printers are used: stereolithographic “Rapidshape D30” and ink-jet “Solidscape 66+”. The geometrical and fitting accuracy as well as the surface roughness are investigated. Findings: It is established that Co-Cr bridges, casted from 3D printed patterns with 50 μm layer thickness, characterize with the largest dimensions – 3.30%-9.14% larger than those of the base model. Decreasing the layer thickness leads to dimensional reduction. The dimensions of the bridges, casted on patterns with 13 μm layer thickness, are 0.17%-2.86% smaller compared to the primary model. The average roughness deviation Ra of the surface of Co-Cr bridges, manufactured using 3D printed patterns, is 3-4 times higher in comparison to the bridge-base model. The greater the layer thickness of the patterns, the higher Ra of the bridges. The silicone replica test shows 0.1-0.2 mm irregular gap between the bridge retainers and abutments of the cast patterns and Co-Cr bridges. Research limitations/implications: Highly precise prosthetic constructions, casted from 3D printed patterns, can be produced only if the specific features of the 3D printed objects are taken in consideration. Practical implications: Present research has shown that the lower the thickness of the printed layer of cast patterns, the higher the dimensional accuracy and the lower the surface roughness. Originality/value: The findings in this study will help specialist in dental clinics and laboratories to choose the right equipment and optimal technological regimes for production of cast patterns with high accuracy and low surface roughness for casting of precise dental constructions.

Surfactant Self-Assemblies Near Contact Lines and their Effect on Wetting by Surfactant Solutions

1994 ◽  
Vol 366 ◽  
Author(s):  
B. Frank ◽  
S. Garoff
Keyword(s):  
Pattern Formation ◽  
Contact Line ◽  
Self Assembly ◽  
Surface Interactions ◽  
Contact Lines ◽  
Dynamic Wetting ◽  
Wetting Behavior ◽  
Wetting Properties ◽  
Surfactant Solutions ◽  
Solid Liquid

ABSTRACTSurfactant self-assembly at the liquid-vapor, solid-liquid, and solid-vapor interfaces controls the wetting behavior of advancing surfactant solutions. While different surfactants exhibit different static and dynamic wetting properties, we show that these behaviors can be understood through an examination of microscopic structures driven by surfactant-surface interactions. We examine surfactant solutions exhibiting complete and partial static wetting as well as spreading by dendritic pattern formation and unsteady, stick-jump behavior. In each case, the observed behavior is related to the structure of the surfactant assemblies in the vicinity of the contact line.

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