Wet anisotropic etching is extensively employed in silicon bulk micromachining to fabricate microstructures for various applications in the field of microelectromechanical systems (MEMS). In addition, it is most widely used for surface texturing to minimize the reflectance of light to improve the efficiency of crystalline silicon solar cells. In wet bulk micromachining, the etch rate is a major factor

Energy crisis and environmental pollution have been one of the major global issues. In this regard, the search for new energy storage materials is cheap, flexible and high-performance supercapacitors electrode which has become intensive. Also, reducing the amount of organic dyes polluting in water is a great significance. Herein, one-step electropolymerization of methylene blue on carbon fiber and

Electronic skin (E-skin) capable of detecting various physical stimuli is required for monitoring external environments accurately. Here, we report an all-soft multiaxial force sensor based on liquid metal microchannel array for electronic skin applications. The proposed sensor is composed of stretchable elastomer and Galinstan, a eutectic gallium-indium alloy, providing a high mechanical flexibility

The present research work reports on the fabrication of ultraviolet (UV) photodetectors using bismuth ferrite (BiFeO3, BFO) thin films with varying thickness. Using the spray pyrolysis technique, BFO thin films were deposited on the glass substrate at 673 K. The deposited BFO thin films were characterized by Raman and FTIR spectroscopic analysis. The morphological analysis reveals uniform grain distribution

We propose a highly sensitive capacitive pressure sensor made of hollow polydimethylsiloxane (PDMS) foam with a three-dimensional network structure. The stiffness of the foam is adjusted by the viscosity of the PDMS solution. The fabricated PDMS-30 (PDMS 30 wt%) foam shows extremely high porosity (> 86%) approximately 19 times that of bare PDMS (PDMS 100 wt%) foam. Capacitive pressure sensors fabricated

An amendment to this paper has been published and can be accessed via the original article.

This paper proposes a new design of bimorph-type electrothermal actuators based on flexible Ni-Co substrates and describes the results of the finite element method (FEM) simulation and performance evaluation of the actuators. In the design of the actuators, a multilayer structure consisting of an adhesion layer, two insulation layers, and a Pt (platinum) heater layer was formed on the Ni-Co flexible

The extraordinary enhancement in heat transfer efficiency of nanofluids at extremely low volume fractions has attracted a lot of attention in identifying the governing mechanisms. The nanoscale effects, Brownian motion (random motion of particles inside the base fluid) and thermophoresis (diffusion of particles due to temperature gradient) are found to be important slip mechanisms in nanofluids. Based

We present a method to fabricate planar metal layers to be used as micromachined mirrors. Released mirrors of pure metal involve severe stress and reveal specific challenges to obtain planar mirror structures. Introducing sub-structures generating corrugated patterns, the metal mirror layers can be mechanically stabilized and undesired mirror bending can be reduced. For our investigations we used different

A comparative study of elastic properties and mode I fracture energy has been presented between conventional carbon fibre (CF)/epoxy and advanced carbon nanotube (CNT)/epoxy laminated composite materials. The volume fraction of CNT fibres has been considered as 15%, 30%, and 60% whereas; the volume fraction of CF has been kept constant at 60%. Three stacking sequences of the laminates viz.[0/0/0/0]

Preterm infants are prone to have higher risks of morbidity, disability and developmental delay compared to term infants. The primitive reflexes, inborn behaviors found in early life development, are shown to be a good tool to assess the integrity of the central nervous system of infants and to predict potential malfunctions. Among these reflexes, the non-nutritive sucking reflex plays an important

Recently, as the concentration of fine dust in the atmosphere has increased due to an increase in the use of fossil fuel power plants, automobiles, and factories, it has been increasingly important to measure fine dust in the atmosphere. This is because exposure to fine dust is closely related to the incidence of respiratory and cardiovascular diseases and eventually affects mortality. In this paper

This paper reports doubly clamped microchannel embedded resonators with two independent and parallel channels integrated for effective sample density tuning for the first time. With the aid of such a unique design, each fluidic channel can be independently accessed thus different liquid samples can be loaded simultaneously. The proposed fluidic resonators are batch fabricated by depositing silicon

Rapid diagnosis and treatment are required when blood clots build up in a blood vessel and clog up the vessel. This study proposes novel smart catheters that can simultaneously diagnose and treat blood vessel disease. This quick treatment increases survival probability and can prevent various complications. In the design of the smart catheters, Pt strain gauges can be used to measure the inside diameter

Deep reactive-ion etching (DRIE) is commonly used for high aspect ratio silicon micromachining. However, scalloping, which is the result of the alternating Bosch process of DRIE, can cause many problems in the subsequent process and degrade device performance. In this work, we propose a simple and effective method to smoothen the scalloping of DRIE trenches. The proposed method utilizes sidewall dry

To pierce through the skin and interact with the first biofluid available, microneedles should be mechanically strong. However, some polymers used to fabricate microneedles yield insufficient strength for the fabrication of arrays (PDMS, highly porous structures, etc.). To enhance mechanical properties, piercing materials can be used. They aim to pierce the skin evenly and dissolve quickly, clearing

In this study, the spring constant of an accelerometer with a liquid-type proof mass was analyzed. Unlike a general solid-type microelectromechanical system accelerometer, the Laplace pressure is considered a restoring force in the analyzed accelerometer. Using a base excitation mathematical model, the sensor output could be estimated for a specific spring constant. Although the estimated sensor output

With the increasing allergy cases worldwide, this study introduces a biodegradable microneedle system to facilitate allergy testing process. Dissolving microneedle provides a minimally invasive manner to go through skin barrier while avoiding needle phobia among patents, especially children. The microneedles were fabricated using copolymer polyvinylpyrrolidone-co-methacrylic acid (PVP-MAA) material

In this paper, we experimentally verified the length (LESC) and the concentration (cESC) of the extended space charge (ESC) layer in front of the electrical double layer (EDL) using the chronopotentiometric measurement and the equivalent circuit model analysis. From the experimentation, the coupled-response of the EDL and the ESC layer was discriminated from the contribution of electro-osmotic flow

Conventional 3D printing methods require the addition of a supporting layer in order to accurately and reliably fabricate the desired final product. However, the use of supporting material is not economically viable, and during the process of removing the supporting material, the shape or the properties of the final product may be distorted. In our previous work, we proposed and demonstrated the concept

Vanadium sulfide (VS2) nanomaterials have been deposited on surface-modified stainless steel mesh (SMSSM) by facial hydrothermal method and subsequent effects of acidic etching on surface morphology and supercapacitive performance of the electrode were studied. The acid etching process improves the coupling interaction between the stainless steel mesh and active materials. The optimized 1% etched SMSSM

Diffusiophoresis near a nanoporous medium is the phenomenon that particles were spontaneously moved from low concentration region to high concentration region. However, unidirectional particle motion impeded further application of this phenomenon and lack of studies about the external convective flow effect such as evaporation through a nanoporous medium were reported. In this work, we investigated

Microfluidic paper-based analytical devices (μPADs) for separating particles have been playing a key role for point-of-care diagnostics in the area of remote settings. While splendid separation methods using μPADs have been explosively developed, they still require external devices inducing external field. In this work, the spontaneous separation method in μPADs was suggested by leveraging convective

This paper presents a computer-controlled multidirectional UV-LED lithography system for 3-D microfabrication. The presented UV-LED system has adopted adjustable or programmable high-intensity UV-LEDs as a light source enabling for photopatterning both thin and thick SU-8 photoresist process. The prototype of the proposed system comprises 5-by-5 surface-mounted type LEDs with customized collimation

We developed a nano field-effect transistor (nanoFET) sensor for detecting ions in the air. Air ions can be measured using a commercial ion counter; however, it is large and expensive equipment, requires airflow to be through a cylinder type electrode or the plate electrode. NanoFET sensor is suitable for monitoring the ion generator module in home appliances like air purification. A nanoFET sensor

Unfrotunately, the original version of the article [1] contained an error in Funding section. It has been brought to our attention by the authors that the funding year was inadvertently published as 2019, instead it should be 2018. The correct Funding section is given below.

Microelectrodes for detection of chemicals present several advantages over conventional sized electrodes. However, rapid and low-cost fabrication of microelectrodes is challenging due to high complexity of patterning equipment. We present the development of a low-cost, customizable inkjet printer for printing nanomaterials including carbon nanotubes for the fabrication of microelectrodes. The achieved

In this paper, we report a thin magnetic micropump embedded in contact lens, which is capable of on-demand one-directional drug delivery. The proposed micropump can be actuated by the external magnetic field whenever needed without the need of battery. A micro check valve was integrated with the micropump for one-directional drug delivery from the micropump to the post-lens tear film. With actuation

In this study, particle focusing phenomena are studied in parallelogram and rectangular cross-sectioned microchannels of varying aspect ratio. In contrast to prior work the microchannels were fabricated using anisotropic wet etching of a Si wafer, plasma bonding, and self-alignment between the Si channel and the PDMS mold. It is shown that the inertial focusing points of the fabricated microchannels

Aberrant expression of microRNA (miRNA) in biological cells is crucial evidence for early diagnosis of cancer. Improvements in molecular detection techniques enabled miRNA to be detected in human blood obtained from liquid biopsies (e.g., Polymerase chain reaction, microcantilever sensor, and surface-enhanced Raman spectroscopy). Despite the advances in molecular detection technology, a simultaneous

We present a highly elastic and wearable piezoresistive strain sensor based on three-dimensional, micro-porous graphene-coated polydimethylsiloxane (PDMS) sponge suitable for being attached on human skin. The proposed strain sensors are simply fabricated by a sugar templating process and dip coating method based graphene ink in a facile and cost effective manner. The fabricated graphene-coated PDMS

This study reports the first comprehensive investigation of separation of the immiscible phases of multiphase droplets in digital microfluidics (DMF) platform. Electrowetting-on-dielectric (EWOD) actuation has been used to mechanically separate the phases. Phase separation performance in terms of percentage residue of one phase into another phase has been quantified. It was conceived that the residue

The development of a DNA microfluidic device with a high speed, low power, and low reagent volume is very critical for real-time genotyping and diagnosis in point-of-care applications. This paper reports a polymer-based thermal cycler for a handheld and battery-powered polymerase chain reaction (PCR) system using a polyimide (PI) film-based micro-fabricated heater module and polymer film microfluidic

Fiber optic based localized surface plasmon resonance (FO-LSPR) sensor is one of the biosensors that detects specific biomolecules and can detect the onset of disease. In this paper, we propose two methods to improve the signal to noise ratio (SNR) of the sensor, which is one of the main characteristics of the FO-LSPR sensor. The first method is to increase the intensity of the sensor by increasing

In the present study, we proposed a fabrication process of anisotropic wetting surfaces with asymmetric grooved parallelogram structures employing basic MEMS processes and micro transfer molding process. A Si substrate and a PDMS mold from Si master were easily self-aligned due to geometrical similarity (all Si wafer have same crystal planes) so that parallelogram microchannels could be formed between

We present the selective laser-induced etching (SLE) process and design guidelines for the fabrication of three-dimensional (3D) microfluidic channels in a glass. The SLE process consisting of laser direct patterning and wet chemical etching uses different etch rates between the laser modified area and the unmodified area. The etch selectivity is an important factor for the processing speed and the

The present work describes the hybridization of two different energy harvesters works simultaneously in a single package. By applying simultaneous mechanical force, two components such as triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) independently produce power. The hybrid device was made with a polymeric cylinder composed of Kapton in the inner wall; a copper coil wound outside

Blood vessels in central nervous system act as a great hurdle for drug delivery to the human brain. They only allow passage of water, some gases, lipid molecules, glucose and amino acid by selective transporter while restricting most of solutes and pathogens to protect brain. A lot of studies have tried to overcome this hurdle by discovering and optimizing brain deliverable drugs however the platforms

Herein, we present a facile fabrication method to prepare the optically transparent, flexible and self-cleanable poly(urethane acrylate) (PUA) superhydrophobic film. The low surface energy siloxane functionalization on the thermally activated µ-patterned PUA/graphene oxide composite (S-PG) was found to be a successful strategy to modify the PUA intrinsic hydrophilicity into superhydrophobic nature

We have rationally designed and developed a fully automated desktop furnace system that enables programmable chemical vapour deposition growth of carbon nanotubes with controlled height, density, and pattern architecture. Comprising several essential components involving a heating furnace, mass flowmeters, and computer controller, the developed system realizes controlled and practical carbon nanotube

In this study, we demonstrate an on-demand delivering and sequential arraying of single microparticles utilizing multiple pneumatic pressure-driven elastomer valves and a deterministic particle arraying mechanism. Two types of separate microfluidic devices are combined: (i) a particle transfer device and (ii) a particle arraying device, to construct a desired particle pattern. The elastomer valve integrated

This paper reports bimodal operation of microchannel resonators towards measurements of properties associated with energy dissipation resulting from travelling particles along with their buoyant masses. Two independent actuation methods are applied for simultaneous operation of the first and second flexural bending modes of cantilever-type microchannel resonators. The first mode is operated in closed

Implementing 3D surface imaging camera systems into miniaturized devices for a variety of 3D applications such as movement recognition, object sensing, and 3D endoscopy has received great attention over the past decade. Recently, various MEMS techniques enabled the fabrication of key optical elements for 3D surface imaging with compact size, reasonable cost, and high yield. This article will overview

We propose a novel localized surface plasmon resonance (LSPR) sensor system based on polymer material. The proposed LSPR system consists of the incident medium with low-loss polymer waveguide and the chemically immobilized plasmonic nanoparticles for on-chip LSPR sensing. Because of low coupling efficiency of conventional methods, usually intricate test equipment such as dark field microscopes equipped

The influence of the air atmosphere on the electrical conductivity of nanocrystalline thin SiC films obtained by method of direct ion deposition on sapphire was studied. Measurements were performed on two series of nc-SiC films with different structure: one series contained mainly 3C-SiC polytype nanocrystals and were denoted as monopolytypic, the second series were a nanoheterostructures based on

A polymer-based tactile sensor with flexibility and multi-directional sensing capability is presented. The proposed sensor consists of a polydimethylsiloxane (PDMS) bump, a polyimide (PI) substrate, Cr/Au electrode lines for electrical connection, NiCr piezoresistors, and an SU-8 support structure. The sensing mechanism is based on piezoresistive effect, in which the resistance of NiCr changes under

This work presents a flexible cable-shaped supercapacitor based on carbon fibers (CFs) coated with graphene flakes (GFs) for wearable electronic applications. The CF bundles were adopted as base materials and the GFs were coated on the surface of CFs using a simple dipping method for the enhancement of the specific surface area and the higher conductivity of flexible electrodes. H2SO4 was mixed with

This paper presents a light detection and ranging (LIDAR) system using electromagnetically actuated two-axis scanning micromirror. The distance measurement with the LIDAR is based on the indirect time-of-flight method using the relative ratio of the accumulated charges in capacitors connected to photodiode pixels, which is determined by the time difference between the transmitted and reflected light

This study proposes the unique method to analyze the cleanliness of the fine metal mask (FMM) used in OLED display manufacturing after FMM cleaning process. We developed a FMM-mimic microstructure as a substitute for the FMM, which can be used for the evaluation of cleaning efficiency. The FMM-mimic microstructure was fabricated using a combination of photolithography, reactive ion etching, anodic

This paper investigates the change of the relative magnitudes of force and impulse components generated by the rotational motion of a hydrophobic carbon rod moving into water from the water surface, by varying the rod length. Whereas added mass force and drag force were dominant regardless of the rod length, buoyancy force and surface tension force were relatively small. For relatively short rod lengths

The coffee ring effect occurs when a droplet of a suspension evaporates on a substrate; this process can separate suspended nanoparticles (NPs) by size as a result of geometric constraints at the contact line of the evaporating droplet. In the study, we used a polydimethylsiloxane (PDMS) stamp to make an even contact line, and we changed the contact angle θ of the droplet by selectively configuring

This work reports the development of a field-deployable and fully handheld fluorometer for environmental water monitoring. Our developed fluorimeter can detect both green algae and cyanobacteria (blue-green algae) while simultaneously differentiating and measuring two different species by selectively measuring chlorophyll a fluorescence from green algae and phycocyanin fluorescence from blue-green

Here, we develop a flexible microrobot enhancing the steerability of a conventional guidewire. To improve steerability, a microrobot is attached to the tip of the guidewire and guided using an external magnetic field generated by an electromagnetic coil system. The flexible microrobot is fabricated via replica-molding and features a body made of polydimethylsiloxane (PDMS) and a single permanent magnet

We present a photolithography scheme for ultra-tall, high-aspect-ratio microstructures. While increased height of microstructures can expand the design capability of various microdevices, it has been challenging to achieve the ultra-tall microstructure, 1 mm or higher, using a well-known negative photoresist, SU-8. One of the reasons is the high absorption rate of 365-nm ultra-violet light during the

In this paper, a stress and fracture study, occurring during the chemical mechanical polishing (CMP) of anodically bonded substrates is presented. The samples contain glass pillars, used to form the glass cavities and a silicon substrate sealing the glass structure, the samples are fabricated using the anodic bonding process. The mechanical stresses of the bonded silicon substrate are simulated using

In this paper, we characterized the behavior of polymer jet from near-field electrospinning onto the inkjet patterned paper with conductive Ag nanoparticles in order to form the controlled three-dimensional nanostructures. Using inkjet patterned paper with conductive ink as a collector, the polymer jet is induced to the pre-patterned shape through the concentrated electric field caused by singularity

In this research, we present the feasibility testing results of a simple distance measurement system using microfabricated scanning micromirrors. Two different configurations have been tested with different types of micromirrors. In the first configuration, Lissajous scan pattern has been generated with horizontal scan frequency of 715 Hz, and the intensity of the laser beam reflected from the object

A volatile organic compound (VOC) sensor array based on metal oxide nanoparticles (MOX NPs) functionalized by metalloporphyrins (MPPs) was demonstrated. The VOC sensor array was composed of four single sensors based on SnO2 NPs/cobalt-porphyrin, SnO2 NPs/zinc-porphyrin, SnO2 NPs/nickel-porphyrin and ZnO NPs/cobalt-porphyrin. The MOX NP/MPP-based sensors were fabricated by drop-casting the MOX NPs dispersion

In the present study, a screen-printed electrode based-sensor with electrochemical detection was developed for rapid and sensitive determination of acetylcholine. At first, the screen-printed carbon electrode was modified by using a magnetic core shell and then was used for voltammetric determination of acetylcholine in ampoule, serum and urine samples. The electrochemical behaviour of acetylcholine

This paper reports the first demonstration of hydrogel conical tip attachment onto quartz tuning fork (QTF) by using an elastomeric tip mold that is soft-lithographically replicated from an electrochemically etched tungsten wire. The tungsten tip of 10–100 nm radius obtained by time-controlled electrochemical etching is replicated with h-polydimethylsiloxane (h-PDMS) to make negative conical tip molds