In this review, PEDOT–PSS is mainly a commercially available PEDOT–PSS, which is a water-dispersible form of the intrinsically conducting PEDOT doped with the water-soluble PSS, including its derivatives, copolymers, analogs (PEDOT:PSSs), even their composites via the chemical or physical modification toward the structure of PEDOT and/or PSS. First, we will focus on discussing the scientific importance of PEDOT–PSS in conjunction with its extraordinary properties and broad multidisciplinary applications in organic/polymeric electronics and optoelectronics from the viewpoint of the historical development and the promising application of representative ECPs. Subsequently, versatile film-forming techniques for the preparation of PEDOT–PSS film electrode were described in details, including common coating approaches and printing techniques, and many emerging preparative methods were mentioned. Then challenges (e.g., conductivity, stability in Water, adhesion to substrate electrode) of PEDOT–PSS film electrode for devices under the high humidity/watery circumstances, especially electrochemical devices are discussed. Fourth, we take PEDOT–PSS film electrode for a relatively new application in sensors as an example, mainly summarized advances in the development of various sensors based on PEDOT–PSSs and their composites in combination with its preparative methods and extraordinary properties. Finally, we give the outlook of PEDOT–PSS for possible applications with the emphasis on PEDOT–PSS film electrode for electrochemical devices, including sensors. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 55, 1121–1150

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/pola.28482

Scientific Importance of Water‐Processable PEDOT–PSS and Preparation, Challenge and New Application in Sensors of Its Film Electrode: A Review

There is an indispensable need for fluid flow rate and direction sensors in various medical, industrial and environmental applications. Besides the critical demands on sensing range of flow parameters (such as rate, velocity, direction and temperature), the properties of different target gases or liquids to be sensed pose challenges to the development of reliable, inexpensive and low powered sensors. This paper presents an overview of the work done on design and development of Microelectromechanical system (MEMS)-based flow sensors in recent years. In spite of using some similar principles, diverse production methods, analysis strategies, and different sensing materials, MEMS flow sensors can be broadly categorized into three main types, namely thermal sensors, piezoresistive sensors and piezoelectric sensors. Additionally, some key challenges and future prospects for the use of the MEMS flow sensors are discussed briefly.

/pdf/design-and-applications-of-mems-flow-sensors-a-review-515rj4x2ar.pdf

Design and applications of MEMS flow sensors: A review

One of the exciting and promising developments in material science today is the design and synthesis of novel low-dielectric-constant polymer materials, which are found to have potential applications in the field of ultralarge-scale integration, capacitors and other electronic circuits as insulating and/or dielectric materials. In this article the new polymer dielectric materials reported in recent years are reviewed, including aromatic (heteroaromatic) polymers, silicon-containing polymers, fluorinated polymers, porous polymers, etc. In summarizing the review, the development, potential applications and future directions of polymer materials with low dielectric constant are discussed. Copyright © 2010 Society of Chemical Industry

Review of polymer materials with low dielectric constant

This work presents a method for 3D printing hair-like structures on both flat and curved surfaces. It allows a user to design and fabricate hair geometries that are smaller than 100 micron. We built a software platform to let users quickly define the hair angle, thickness, density, and height. The ability to fabricate customized hair-like structures not only expands the library of 3D-printable shapes, but also enables us to design passive actuators and swipe sensors. We also present several applications that show how the 3D-printed hair can be used for designing everyday interactive objects.

/pdf/cilllia-3d-printed-micro-pillar-structures-for-surface-dgjbhtjvyq.pdf

Cilllia: 3D Printed Micro-Pillar Structures for Surface Texture, Actuation and Sensing

Simultaneous improvement of mechanical properties and lowering of the dielectric constant occur when films grown from the cyclic monomer tetravinyltetramethylcyclotetrasiloxane (V4D4) via initiated chemical vapor deposition (iCVD) are thermally cured in air. Clear signatures from silsesquioxane cage structures in the annealed films appear in the Fourier transform IR (1140 cm−1) and Raman (1117 cm−1) spectra. The iCVD method consumes an order of magnitude lower power density than the traditional plasma-enhanced CVD, thus preserving the precursor's delicate ring structure and organic substituents in the as-deposited films. The high degree of structural retention in the as-deposited film allows for the beneficial formation of intrinsically porous silsesquioxane cages upon annealing in air. Complete oxidation of the silicon creates ‘Q’ groups, which impart greater hardness and modulus to the films by increasing the average connectivity number of the film matrix beyond the percolation of rigidity. The removal of labile hydrocarbon moieties allows for the oxidation of the as-deposited film while simultaneously inducing porosity. This combination of events avoids the typical trade-off between improved mechanical properties and higher dielectric constants. Films annealed at 410 °C have a dielectric constant of 2.15, and a hardness and modulus of 0.78 and 5.4 GPa, respectively. The solvent-less and low-energy nature of iCVD make it attractive from an environmental safety and health perspective.

Ultralow Dielectric Constant Tetravinyltetramethylcyclotetrasiloxane Films Deposited by Initiated Chemical Vapor Deposition (iCVD)

This paper reports on the creation of a low-cost, disposable sensor for low flow velocities, constructed from extruded micro-sized 'hair' of conducting polymer PEDOT. These microstructures are inspired by hair strands found in many arthropods and chordates, which play a prime role in sensing air flows. The paper describes the fabrication techniques and the initial prototype testing results toward employing this sensing mechanism in applications requiring sensing of low flow rates such as a flow sensor in neonatal resuscitators. The fabricated 1000 μm long, 6 μm diameter micro-hairs mimic the bending movement of tactile hair strands to sense the velocity of air flow. The prototype sensor developed is a four-level direct digital-output sensor and is capable of detecting flow velocities of up to 0.97 m s(-1).

Bio-inspired flow sensor from printed PEDOT:PSS micro-hairs

Analysis of HSG-7000 silsesquioxane-based low-k dielectric hot plate curing using Raman spectroscopy

Non-volatile memory with zinc oxide nanoparticles embedded in a hybrid polymethylsilsesquioxane layer

We report the creation of a low flow rate sensor from PEDOT micro-hairs. The hairs are printed as pipette-defined depositions using a nanopositioning system. The printing technique was developed for fabricating structures in 2D and 3D. Here micro-hairs with diameters of 4:4 m were repeatedly extruded with constant heights. These hairs were then applied to produce a prototype flow rate sensor, which was shown to detect flows of 3:5 l min 1 . Structural analysis was performed to demonstrate that the design can be modified to potentially observe flows as low as 0:5 l min 1 . The results are extended to propose a practical digital flow rate sensor. (Some figures may appear in colour only in the online journal)

K.C. Aw

Papers

Bio-inspired flow sensor from printed PEDOT:PSS micro-hairs

Analysis of HSG-7000 silsesquioxane-based low-k dielectric hot plate curing using Raman spectroscopy

Non-volatile memory with zinc oxide nanoparticles embedded in a hybrid polymethylsilsesquioxane layer

A novel air flow sensor from printed PEDOT micro-hairs

An organic thin film transistor based non-volatile memory with zinc oxide nanoparticles