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1 – 10 of 350
Article
Publication date: 21 November 2008

Ehsan Saeedi, Samuel Kim and Babak A. Parviz

The paper's aim is to present a method for integrating high‐performance circuit components onto flexible substrates using self‐assembly. The basic process of self‐assembly at the…

Abstract

Purpose

The paper's aim is to present a method for integrating high‐performance circuit components onto flexible substrates using self‐assembly. The basic process of self‐assembly at the micrometer‐scale is reviewed and recent work in building functional parts such as silicon transistors and compound semiconductor light emitting diodes, as well as their integration onto flexible plastic templates, is reported.

Design/methodology/approach

A micron‐scale self‐assembly method was used for building flexible circuits. In micron‐scale self‐assembly, functional micro‐components are independently microfabricated and subsequently allowed to self‐assemble on a template with electrical interconnects and corresponding binding sites in a fluid.

Findings

The self‐assembly process can achieve heterogeneous integration with a potentially very high yield. Successful assembly of functional micro‐components such as LEDs and transistors on plastic has been demonstrated.

Originality/value

The paper demonstrates fabrication techniques for free‐standing micro‐components with novel designs, low‐temperature fabrication on thin plastic sheets, and using capillary‐gravity‐based self‐assembly for the integration of crystalline inorganic semiconductor components onto unconventional substrates such as flexible polymers.

Details

Circuit World, vol. 34 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 1 August 2008

Robert Bogue

The purpose of this paper is to provide a review of recent progress in self‐assembly technology, principally in the microelectronics context.

1651

Abstract

Purpose

The purpose of this paper is to provide a review of recent progress in self‐assembly technology, principally in the microelectronics context.

Design/methodology/approach

First, the paper discusses the application of nanoscale self‐assembly techniques to microelectronic and related components and then considers research involving larger devices.

Findings

The paper shows that a range of self‐assembly techniques is being used to fabricate both production and experimental microelectronic devices, often with the aim of developing alternatives to copper wire interconnects. Other, experimental self‐assembly techniques are being developed for the packaging and mounting of microelectronic components on substrates.

Originality/value

Provides a useful, detailed review of the use of self‐assembly techniques at the nanoscale, microscale and macroscale.

Details

Assembly Automation, vol. 28 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 26 April 2011

N.B. Crane, J. Tuckerman and G.N. Nielson

Additive manufacturing (AM) offers substantial flexibility in shape, but much less flexibility in materials and functionality – particularly at small size scales. A system for…

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Abstract

Purpose

Additive manufacturing (AM) offers substantial flexibility in shape, but much less flexibility in materials and functionality – particularly at small size scales. A system for automatically incorporating microscale components would enable the fabrication of objects with more functionality. The purpose of this paper is to consider the potential of self‐assembly to serve as an automated programmable integration method. In particular, it addresses the ability of random self‐assembly processes to successfully assemble objects with high performance despite the possibility of assembly errors.

Design/methodology/approach

A self‐assembled thermoelectric system is taken as a sample system. The performance expectations for these systems are then predicted using modified one‐dimensional models that incorporate the effects of random errors. Monte‐Carlo simulation is used to predict the likely performance of self‐assembled thermoelectric systems and evaluate the impact of key process and system design parameters.

Findings

While assembly yield can drop quickly with increasing numbers of assembled parts, large functional assemblies can be constructed by arranging components in parallel to provide redundancy. In some cases, the performance losses are minimal. Alternatively, sensing can be incorporated to identify perfect assemblies. For small assemblies, the probability of perfection may be high enough to achieve an acceptable assembly rate. Small assemblies could then be combined into larger functional systems.

Originality/value

The paper identifies two strategies that can guide the development of AM processes that incorporate miniature components to increase the system functionality. The analysis shows that this may be possible despite significant errors in the self‐assembly process because systems may be tolerant of significant assembly errors.

Details

Rapid Prototyping Journal, vol. 17 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 27 September 2011

Robert Bogue

The purpose of this paper is to review recent developments in micro‐scale assembly technologies, primarily in the context of microsystems based on three‐dimensional (3D…

Abstract

Purpose

The purpose of this paper is to review recent developments in micro‐scale assembly technologies, primarily in the context of microsystems based on three‐dimensional (3D) micro‐electromechanical systems (MEMS) and micro‐opto‐electromechanical systems (MOEMS) technologies.

Design/methodology/approach

Following a brief introduction, this paper first discusses the problems associated with the assembly of micro‐components and then considers the role of robots and self‐assembly technologies. This is followed by a brief summary and conclusion.

Findings

Experimental robotic systems have been developed and used for the assembly of a wide range of MEMS and MOEMS components. Various self‐assembly technologies offer prospects for massively parallel microassembly but have yet to achieve the success of the robotic approach. Some work has sought to combine the best feature of both approaches but as yet, no technologies have been developed that can rapidly, accurately and cost‐effectively assemble micro‐components into hybrid 3D MEMS/MOEMS devices in a true production environment.

Originality/value

This paper provides a detailed review of recent progress in the robotic and self‐assembly of micro‐components.

Details

Assembly Automation, vol. 31 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 20 September 2023

Zhifang Wang, Quanzhen Huang and Jianguo Yu

In this paper, the authors take an amorphous flattened air-ground wireless self-assembling network system as the research object and focus on solving the wireless self-assembling…

Abstract

Purpose

In this paper, the authors take an amorphous flattened air-ground wireless self-assembling network system as the research object and focus on solving the wireless self-assembling network topology instability problem caused by unknown control communication faults during the operation of this system.

Design/methodology/approach

In the paper, the authors propose a neural network-based direct robust adaptive non-fragile fault-tolerant control algorithm suitable for the air-ground integrated wireless ad hoc network integrated system.

Findings

The simulation results show that the system eventually tends to be asymptotically stable, and the estimation error asymptotically tends to zero with the feedback adjustment of the designed controller. The system as a whole has good fault tolerance performance and autonomous learning approximation performance. The experimental results show that the wireless self-assembled network topology has good stability performance and can change flexibly and adaptively with scene changes. The stability performance of the wireless self-assembled network topology is improved by 66.7% at maximum.

Research limitations/implications

The research results may lack generalisability because of the chosen research approach. Therefore, researchers are encouraged to test the proposed propositions further.

Originality/value

This paper designs a direct, robust, non-fragile adaptive neural network fault-tolerant controller based on the Lyapunov stability principle and neural network learning capability. By directly optimizing the feedback matrix K to approximate the robust fault-tolerant correction factor, the neural network adaptive adjustment factor enables the system as a whole to resist unknown control and communication failures during operation, thus achieving the goal of stable wireless self-assembled network topology.

Article
Publication date: 5 January 2023

Jundong He and Xinguang Lv

The purpose of this study is to modify the FDM 3D printer to print with polystyrene (PS) microspheres as the printing material, thus enabling bottom-up structural color printing…

Abstract

Purpose

The purpose of this study is to modify the FDM 3D printer to print with polystyrene (PS) microspheres as the printing material, thus enabling bottom-up structural color printing and evaluating structural color printing.

Design/methodology/approach

This study chose a range of different heated bed temperatures to determine a suitable temperature for accelerating the self-assembly of photonic crystals and printing structural colors on various substrates. In addition, this study enhanced the structural color by doping PS microspheres with different contents of Acid Black 210 dye and evaluated the color-enhanced structural color by eye and spectrophotometer under different light sources.

Findings

The results show that the modified 3D printer can be used for structural color printing, and 50°C is determined as the heated bed temperature. There are significant differences in structural colors when printing under different color backgrounds and material substrates, and corresponding suitable substrates should be selected according to the application. The doping of PS microspheres with varying contents of dye results in different color levels of structural color. As with pigment colors, the visual perception of structural color varies when viewed under different light sources.

Originality/value

This paper proposes to print structural colors low-costly, analyze structural colors under substrate and light source conditions, and expand the structural color gamut by enhancing structural colors, which has positive implications for further research on structural colors as printing colors.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 29 May 2023

Lingyun Cao, Shuaibin Ren, ZhengHao Zhou, Xuening Fei and Changliang Huang

This study aims to fabricate a cool phthalocyanine green/TiO2 composite pigment (PGT) with high near-infrared (NIR) reflectance, good color performance and good heat-shielding…

Abstract

Purpose

This study aims to fabricate a cool phthalocyanine green/TiO2 composite pigment (PGT) with high near-infrared (NIR) reflectance, good color performance and good heat-shielding performance under sunlight and infrared irradiation.

Design/methodology/approach

With the help of anionic and cationic polyelectrolytes, the PGT composite pigment was prepared using a layer-by-layer assembly method under wet ball milling. Based on the light reflectance properties and color performance tested by ultraviolet-visible-NIR spectrophotometer and colorimeter, the preparation conditions were optimized and the properties of PGT pigment with different assembly layers (PGT-1, PGT-3, PGT-5 and PGT-7) were compared. In addition, their heat-shielding performance was evaluated and compared by temperature rise value for their coating under sunlight and infrared irradiation.

Findings

The PGT pigment had a core/shell structure, and the PG thickness increased with the self-assembly layers, which made the PGT-3 and PGT-7 pigment show higher color purity and saturation than PGT-1 pigment. In addition, the PGT-3 and PGT-7 pigment showed 11%–16% lower light reflectance in the visible region. However, their light reflectance in the NIR region was similar. Under infrared irradiation the PGT-5 and PGT-7 pigment coating showed 1.1°C–3.4°C and 1.3°C–4.7°C lower temperature rise value than PGT-1 pigment coating and physical mixture pigment coating, respectively. And under sunlight the PGT-3 pigment coating showed 1.5–2.6°C lower temperature rise value than the physical mixture pigment coating.

Originality/value

The layer-by-layer assembling makes the core/shell PGT composite pigment possess low visible light reflectance, high NIR reflectance and good heat-shielding performance.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 April 2014

Eujin Pei

This feature article aims to review state-of-the-art developments in additive manufacture, in particular, 4D printing. It discusses what it is, what research has been carried out…

2807

Abstract

Purpose

This feature article aims to review state-of-the-art developments in additive manufacture, in particular, 4D printing. It discusses what it is, what research has been carried out and maps potential applications and its future impact.

Design/methodology/approach

The article first defines additive manufacturing technologies and goes on to describe the state-of-the-art. Following which the paper examines several case studies and maps a trend that shows an emergence of 4D printing.

Findings

The case studies highlight a particular specialization within additive manufacture where the use of adaptive, biomimetic composites can be programmed to reshape, or have embedded properties or functionality that transform themselves when subjected to external stimuli.

Originality/value

This paper discusses the state-of-the-art of additive manufacture, discussing strategies that can be used to reduce the print process (such as through kinematics); and the use of smart materials where parts adapt themselves in response to the surrounding environment supporting the notion of self-assemblies.

Details

Assembly Automation, vol. 34 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 11 January 2011

C. Wang, P. Yan, S. Wang, X. Bai, J. Yuan, E. Yan and Z. Huang

The purpose of this paper is to investigate the preparation process and the photoluminescent properties of poly‐(phenylene vinylene) (PPV)/polyvinyl alcohol (PVA)/Ag2S composite…

Abstract

Purpose

The purpose of this paper is to investigate the preparation process and the photoluminescent properties of poly‐(phenylene vinylene) (PPV)/polyvinyl alcohol (PVA)/Ag2S composite nanofibres.

Design/methodology/approach

A simple method coupling electrospinning technology and in situ self‐assembly was used to prepare PPV/PVA/Ag2S nanofibres from the solution containing precursory PPV, PVA and silver nitrate (AgNO3). The photoluminescent properties of the PPV/PVA/Ag2S composite nanofibres were characterised by fluorescence microscopy and eclipse fluorescence spectrophotometer.

Findings

The Ag2S nanoparticles were well dispersed in the PPV/PVA/Ag2S composite nanofibres, and their dimension was in the range of 10‐40 nm. Excessive doping of Ag2S nanoparticles will lead to rough and uneven fibres' surface.

Research limitations/implications

The size of Ag2S nanoparticles in the fibres was not uniform enough and the orientation of composite nanofibres was hardly controlled.

Practical implications

The coupling of electrospinning technology and in situ self‐assembly opened a new gate for preparing other nanoparticles doped composite nanofibres.

Originality/value

The in situ growing of Ag2S nanoparticles in PPV nanofibre improved the excellent properties of composite nanofibres. The morphology of composite nanofibres can be efficaciously controlled via adjusting the ratio between AgNO3 and polymer. The obtained PPV/PVA/Ag2S composite nanofibres will have potential applications in nano‐optoelectronic devices.

Details

Pigment & Resin Technology, vol. 40 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 6 July 2021

Jing Wang, Hongying Mi, Weigui Zhou, Xin Yang and Yan He

This study aims to the preparation and tribological characteristics of graphene/triangular copper nanoplate composites (abbreviated as GN/Cu nanoplates) as grease additive and…

Abstract

Purpose

This study aims to the preparation and tribological characteristics of graphene/triangular copper nanoplate composites (abbreviated as GN/Cu nanoplates) as grease additive and clarifies the growth mechanism and tribological mechanism of GN/Cu nanoplates by different analysis methods. In this paper, it is expected to alleviate the problems of easy aggregation and poor dispersion stability of graphene in lubricants and provide theoretical support for the application of graphene and its composites in the tribology field.

Design/methodology/approach

In this study, the GN/Cu nanoplates have been successfully prepared by the electrostatic self-assembly method. The structural characteristics of GN/Cu nanoplates were analyzed via transmission electron microscopy and X-ray diffraction. Then the tribological properties of GN/Cu nanoplates were investigated under different loads with SRV-IV [Schwingung, Reibung, Verschleiß (German); oscillating, friction, wear (English translation)] tribotester. White-light interferometry was applied to quantify the wear loss of the disk. The element chemical state on worn surfaces was analyzed by an X-ray photoelectron spectroscope to clarify the tribological mechanism of graphene composites.

Findings

The electrostatic force between the negative charge of graphene and the positive charge of triangular copper nanoplates promotes the self-assembly of GN/Cu nanoplates. With the addition of GN/Cu nanoplates, the wear loss and average friction coefficient under the load of 200 N have been decreased by 72.6% and 18.3%, respectively. It is concluded that the combined action of graphene deposition film and the copper melting film formed on the worn surface could effectively improve the antiwear ability and friction reduction performance of the grease.

Originality/value

This manuscript fulfills a new approach for the preparation of GN/Cu nanoplates. At the same time, its tribological properties and mechanism as a lubricating additive were studied which provide theoretical support for the application of graphene and its composites in the tribology field.

Details

Industrial Lubrication and Tribology, vol. 73 no. 5
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 350