Complex Three-dimensional Microstructures Research Articles

Multiscale characterisation study on the effect of heat treatment on the microstructure of additively manufactured 316L stainless steel

Additively manufactured 316L components are known to exhibit complex three-dimensional microstructures on multiple length-scales. The effect of heat treatment on the stability of grains and dislocation cell structures within the microstructure has previously been investigated but there are appreciable disagreements surrounding the nature of the texture that is present in the specimens, and there is also limited published work on the compositional homogeneity of specimens, particularly on the atomic scale, after heat treatments. In this study, we investigate the effect of applying two different heat treatments to 316L components produced by laser powder bed fusion before characterising them using a combination of electron microscopy and atom probe tomography. The importance of using multiple characterisation techniques, which span from the nanometre to micrometre scale, in addition to carefully and accurately describing analysis methods when investigating the evolution of the microstructure of additively manufactured 316L steels is demonstrated. Our EBSD (Electron Back Scatter Diffraction) results show the presence of a strong texture in the build direction of the samples, and a reduction in morphological texture as a result of heat treatment. TEM (Transmission Electron Microscopy) results indicate a dissolution of the dislocation cell structure that forms during solidification. Atom probe tomography was used to investigate compositional homogeneity in the samples and indicated that there are regions enriched in Cr, Mn, Mo, and Ni in the As-Printed samples that are likely associated with the dislocation cell walls. The atom probe results also reveal the presence of impurities, such as Co, which were not detected in the feedstock powder.

Characterizing the microstructures of mammalian enamel by synchrotron phase contrast microCT

The enamel of mammalian teeth is a highly mineralized tissue that must endure a lifetime of cyclic contact and is inspiring the development of next-generation engineering materials. Attempts to implement enamel-inspired structures in synthetic materials have had limited success, largely due to the absence of a detailed understanding of its microstructure. The present work used synchrotron phase-contrast microCT imaging to evaluate the three-dimensional microstructure of enamel from four mammals including Lion, Gray Wolf, Snow Leopard, and Black Bear. Quantitative results of image analysis revealed that the decussation pattern of enamel consists of discrete diazone (D) and parazone (P) bands of rods organized with stacking arrangement of D+/P/D-/P in all mammals evaluated; the D+ and D- refer to distinct diazone bands with juxtaposed rod orientations from the reference plane. Furthermore, the rod orientations in the bands can be described in terms of two principal angles, defined here as the pitch and yaw. While the pitch angle increases from the outer enamel to a maximum (up to ≈ 40°) near the dentin enamel junction, minimal spatial variations are observed in yaw across the enamel thickness. There are clear differences in the decussation parameters of enamel across species that are interpreted here with respect to the structural demands placed on their teeth. The rod pitch and band width of enamel are identified as important design parameters and appear to be correlated with the bite force quotient of the four mammals evaluated. Statement of significanceThe multi-functionality of tooth enamel requires both hardness and resistance to fracture, properties that are generally mutually exclusive. Ubiquitous to all mammalian teeth, the enamel is expected to have undergone adaptations in microstructure to accommodate the differences in diet, body size and bite force across animals. For the first time, we compare the complex three-dimensional microstructure of enamel from teeth of multiple mammalian species using synchrotron micro-computed tomography. The findings provide new understanding of the “design” of mammalian enamel microstructures, as well as how specific parameters associated with the decussation of rods appear to be engineered to modulate its fracture resistance.

Advanced photonic and optofluidic devices fabricated in glass via femtosecond laser micromachining [Invited

Thanks to its unique properties, glass plays a fundamental role in science and technology, especially in optics and photonics. For instance, its transparency has been exploited in the last decades for efficiently guiding light in optical fibers for long distances, while its versatility makes it the perfect material in different research fields, ranging from fundamental science to biology and chemistry. On the occasion of the International Year of Glass, we would like to discuss a powerful microfabrication technique for devices in this material: femtosecond laser micromachining (FLM). This technique can process different types of glass, and thanks to the nonlinear nature of the induced modification, it enables the fabrication of complex three-dimensional micro-structures capable of guiding light or transporting fluids. The purpose of this review article is to celebrate the multidisciplinary nature of FLM by discussing, without claim for completeness and after a brief introduction about the process, a selection of its applications in the diverse fields of biology, strong-field physics, and astronomy.

Burr removal from high-aspect-ratio micro-pillars using ultrasonic-assisted abrasive micro-deburring

The demand for high-aspect-ratio microstructures is ever increasing in the fields of microelectromechanical systems, biomedicine, aerospace, telecommunication, and heat transfer. Mechanical micromachining processes have a distinct advantage over lithography-based processes for machining complex three-dimensional microstructures on a variety of materials with high accuracy and surface finish. But the tool-based micromachining operations face inherent issues in the form of excessive burr formation, which needs to be addressed by post-machining burr removal operations. In this study, an ultrasonic-assisted abrasive micro-deburring process employing a probe sonotrode and abrasive particles has been investigated for deburring high-aspect-ratio micro-pillars machined on aluminium 6061 and copper. Deburring of micromilled pillars of aspect ratio 5:1 has been achieved while maintaining pillar integrity. The mechanism of deburring has been observed to be mainly by the impact of the abrasive particles with a minor role played by liquid cavitation. Burr reduction as high as 88.75% for Al 6061 and 90.1% for copper has been achieved in a short processing time of 10 s. This is a significantly faster process than other ultrasonic cavitation-based deburring processes described in literature (deburring time ranging from 60 min to a few hours). With proper control of the process parameters like stand-off distance and power, burr removal has been achieved while maintaining the integrity of the micro-pillars. Pure water cavitation has also been studied for comparison, which has resulted in a burr removal by 51.5% and 53.1% for Al 6061 and copper, respectively. Upon proper selection of the process parameters, this process can be a viable alternative to existing deburring methods in terms of minimal processing time and structure damage.

3D-Printed Complex Microstructures with a Self-Sacrificial Structure Enabled by Grayscale Polymerization and Ultrasonic Treatment.

Complex three-dimensional (3D) microstructures are attracting more and more attention in many applications such as microelectromechanical systems, biomedical engineering, new materials, new energy, environmental protection, and wearable electronics. However, fabricating complex 3D microstructures by 3D printing techniques, especially those with long suspended structures, needs to introduce additional supporting structures, which are difficult to be removed. Here, we propose a simple method in which the supporting structures can be easily removed by optimizing their size and the grayscale value working with ultrasonic treatment in ethanol solution. The 3D microstructures and the supporting structures made of the same insoluble materials are fabricated simultaneously by using a projection microstereolithography system with a dynamic mask. The results demonstrate that the supporting structures play a key role in the fabrication of the long suspended structures while they can be easily removed. The removal time decreases with the increase in the height of the supporting microstructures, and the breaking force and shearing force of the supporting structures increase with the increase in their grayscale and the diameter. In addition, theory and the multiphysics simulation validate that the stress concentration at the top and the bottom of the supporting structures due to the cavitation from ultrasonic vibration dominates the removal of the supporting structures. Finally, a tree-like structure is precisely fabricated by using our method. The present study provides a new way for the removal of the supporting structures for 3D printed suspended microstructures.

A review on multi nozzle electrohydrodynamic inkjet printing system for MEMS applications

New microproducts require to utilize the variety of materials. Their complex three-dimensional microstructures have big aspect ratios. This ability to fabricate geometrically complicated 3D microstructures provides some additional profits to the additive manufacturing systems over traditional methods. Among the enormous variety of micro-products, depending on the mixtures of usefulness of the product and fundamentals of operation, the foremost types are micro-opto-electro-mechanical systems, micro electromechanical systems, micro-optical electronics systems and microelectronic products. Electrohydrodynamic inkjet printing is an innovative high-resolution technology of inkjet printing which has the benefits of being a non-contact, maskless, additive and direct-write methods. The resolution of printing of EHD surpasses by approx. two orders of magnitude compared to the general inkjet printing methods. It has been used mostly in cases of nano or micro manufacturing of very small objects for modelling of a big range of constituents on different substrates having the alternatives of either Drop-On-Demand mode or continuous mode. It is considered to be a capable substitute to thermal and piezoelectric based inkjet printing methods since it has a unique quality of producing small jet or droplets in comparison to the nozzle orifice. Several advantages in fine patterning are presented by EHD inkjet printing processes, but the little manufacturing speed of EHD inkjet printing is an unadorned disadvantage that has been hindering its probable extensive uses in the industry of electronics. To overcome this restriction, the direct printing of colloidal solutions with the help of multiple nozzle EHD inkjet printing method is used. This review offers a short account of multiple-nozzle electrohydrodynamic inkjet printing of colloidal solutions for its application in MEMS.

Manufacturing of 3D Helical Microswimmer by AFM Micromanipulation for Microfluidic Applications

Manufacturing of microsystems based on complex three-dimensional microstructures requires critical steps such as mass calibrations and integration process. However, such steps involve several manipulation steps which are not well controlled thus the fragile 3D microstructures could be damaged or destroyed. In this work, we have demonstrated an AFM based direct mass measurement and manufacturing of 3D helical microswimmer. The proposed method shows to be rapid, repeatable and minimally-destructive thanks to the precise force control and manipulation by AFM. The proposed micromanipulation steps consist of the pick-measure-integrate manipulation steps using van der Waals force-based attachment and the mass measurement by resonant frequency shift. For the testing structures, we fabricated the 6 different types of 3D helical microswimmers vertically fabricated on the conical shape microneedle supports for uniform surface metallization and facile detachment. With the mass measurement sensitivity of 25 Hz/pg and the direct integration to microfluidics, we successfully demonstrated the 3D propulsion and non-contact micromanipulation by 3D helical microswimmer in microfluidics.

Gentle method for removing metal and restoring function after scanning electron microscopy

An etching process is demonstrated for removing noble metal from microstructures to restore their original function after being characterized by scanning electron microscopy (SEM). Using neither aggressive acids nor high temperatures, the etching method gently removes gold/palladium alloys from complex three-dimensional microstructures, preserving their structural form. To explore the efficacy of the etching process, polymeric photonic crystals and monolithic microstructures were fabricated, metal coated, etched, and then structurally and optically characterized. Metal coating substantially diminishes the optical functional and transmission of the microstructures. SEM imaging performed throughout a series of metal sputtering, etching, and resputtering shows that the etching process does not significantly alter the form of a microstructure. Measurements of optical transmission using a scanned-optical-fiber system confirm that the etchant removes the metal and restores the optical properties of the microstructures.

Acoustic Field-Assisted Two-Photon Polymerization Process

Abstract This study successfully integrates acoustic patterning with the Two-Photon Polymerization (TPP) process for printing nanoparticle–polymer composite microstructures with spatially varied nanoparticle compositions. Currently, the TPP process is gaining increasing attention within the engineering community for the direct manufacturing of complex three-dimensional (3D) microstructures. Yet the full potential of TPP manufactured microstructures is limited by the materials used. This study aims to create and demonstrate a novel acoustic field-assisted TPP (A-TPP) process, which can instantaneously pattern and assemble nanoparticles in a liquid droplet, and fabricate anisotropic nanoparticle–polymer composites with spatially controlled particle–polymer material compositions. It was found that the biggest challenge in integrating acoustic particle patterning with the TPP process is that nanoparticles move upon laser irradiation due to the photothermal effect, and hence, the acoustic assembly is distorted during the photopolymerization process. To cure acoustic assembly of nanoparticles in the resin through TPP with the desired nanoparticle patterns, the laser power needs to be carefully tuned so that it is adequate for curing while low enough to prevent the photothermal effect. To address this challenge, this study investigated the threshold laser power for polymerization of TPP resin (Pthr) and photothermal instability of the nanoparticle (Pthp). Patterned nanoparticle–polymer composite microstructures were fabricated using the novel A-TPP process. Experimental results validated the feasibility of the developed acoustic field-assisted TPP process on printing anisotropic composites with spatially controlled material compositions.

A comparison, using X-ray micro-computed tomography, of the architecture of cancellous bone from the cervical, thoracic and lumbar spine using 240 vertebral bodies from 10 body donors.

The vertebral trabecular bone has a complex three-dimensional microstructure with an inhomogeneous morphology. Correct identification and assessment of the weakest segments of the cancellous bone may lead to better prediction of fracture risk. The aim of this study was to compare cancellous bone from 240 vertebrae of the cervical, thoracic and lumbar spine of ten body donors with osteoporosis in regard to bone volume fraction (BVF), trabecular thickness, separation, trabecular number and degree of anisotropy, to ascertain why cervical vertebrae rarely fracture, even with severe osteoporosis. Samples were obtained from all vertebrae with a Jamshidi needle (8 Gauge). The investigations were performed with a micro-computed tomography (micro-CT) device (SKYSCAN 1172, RJL Micro & Analytic GmbH, Karlsdorf-Neuthard, Germany). Existing vertebral fractures and the bone mineral density of the lumbar spine were assessed with quantitative CT. Regarding the micro-CT parameters, statistically significant differences were observed between the various sections of the spine. We found a higher BVF, trabecular number and trabecular thickness, as well as a lower trabecular separation of the cervical vertebrae compared to other vertebrae. In addition, the degree of anisotropy in the cervical spine is lower than in the other spinal column sections. These results are age and sex dependent. Thus, the cervical spine has special structural features, whose causes must be determined in further investigations.

A combined 3D printing/CNC micro-milling method to fabricate a large-scale microfluidic device with the small size 3D architectures: an application for tumor spheroid production

The fabrication of a large-scale microfluidic mold with 3D microstructures for manufacturing of the conical microwell chip using a combined projection micro-stereolithography (PµSL) 3D printing/CNC micro-milling method for tumor spheroid formation is presented. The PµSL technique is known as the most promising method of manufacturing microfluidic chips due to the possibility of creating complex three-dimensional microstructures with high resolution in the range of several micrometers. The purpose of applying the proposed method is to investigate the influence of microwell depths on the formation of tumor spheroids. In the conventional methods, the construction of three-dimensional microstructures and multi-height chips is difficult, time-consuming, and is performed using a multi-step lithography process. Microwell depth is an essential parameter for microwell design since it directly affects the shear stress of the fluid flow and the diffusion of nutrients, respiratory gases, and growth factors. In this study, a chip was made with microwells of different depth varying from 100 to 500 µm. The mold of the microwell section is printed by the lab-made PµSL printer with 6 and 1 µm lateral and vertical resolutions. Other parts of the mold, such as the main chamber and micro-channels, were manufactured using the CNC micro-milling method. Finally, different parts of the master mold were assembled and used for PDMS casting. The proposed technique drastically simplifies the fabrication and rapid prototyping of large-scale microfluidic devices with high-resolution microstructures by combining 3D printing with the CNC micro-milling method.

A machine learning framework for the temporal evolution of microstructure during static recrystallization of polycrystalline materials simulated by cellular automaton

Reduced-order models of process-structure evolution linkages play a central role in the discovery and development of new/improved materials and their deployment in advanced technologies. In this paper, a novel machine learning framework is developed for capturing the temporal evolution of microstructures during static recrystallization of face-centered cubic (FCC) polycrystalline materials and is demonstrated on a collection of simulation data produced using cellular automata. This new framework first establishes a suitable low-dimensional representation of the polycrystalline microstructures based on 2-point spatial correlations expressed in a generalized spherical harmonics (GSH) basis. Second, a Gaussian process autoregression (GPAR) time-series modeling approach is employed to establish the desired reduced-order process-structure evolution model. It is demonstrated that the framework presented in this paper produces remarkably accurate and robust reduced-order models for the problem studied, in spite of the highly complex three-dimensional (3-D) microstructures involved.

A microstructural-based approach to model magneto-viscoelastic materials at finite strains

Magneto-active polymers (MAPs) consist of a polymeric matrix filled with magnetisable particles. MAPs may change their mechanical properties (i.e., stiffness) and/or mechanical deformation upon the application of an external magnetic stimulus. Mechanical responses of MAPs can be understood as the combined contributions of both polymeric matrix and magnetic particles. Moreover, the magnetic response is defined by the interaction between magnetisable particles and the external field. Common approaches to model MAPs are based on phenomenological continuum models, which are able to predict their magneto-mechanical behaviour but sometimes failed to illustrate specific features of the underlying physics. To better understand the magneto-mechanical responses of MAPs and guide their design and manufacturing processes, this contribution presents a novel continuum constitutive model originated from a microstructural basis. The model is formulated within a finite deformation framework and accounts for viscous (rate) dependences and magneto-mechanical coupling. After the formulations, the model is calibrated with a set of experimental data. The model is validated with a wide range of experimental data that show its predictability. Such a microstructurally-motivated finite strain model will help in designing MAPs with complex three-dimensional microstructures.

Printability of photo-sensitive nanocomposites using two-photon polymerization

Abstract Two-photon polymerization direct laser writing (TPP DLW) is an emerging technology for producing advanced functional devices with complex three-dimensional (3D) micro-structures. Tremendous efforts have been devoted to developing two-photon polymerizable photo-sensitive nanocomposites with tailored properties. Light-induced reconfigurable smart materials such as liquid crystalline elastomers (LCEs) are promising materials. However, due to the difficulties in designing two-photon polymerizable liquid crystal monomer (LCM) nanocomposite photoresists, it is challenging to fabricate true 3D LCE micro-structures. In this paper, we report the preparation of photo-sensitive LCE nanocomposites containing photothermal nanomaterials, including multiwalled carbon nanotubes, graphene oxide and gold nanorods (AuNRs), for TPP DLW. The printability of the LCE nanocomposites is assessed by the fidelity of the micro-structures under different laser writing conditions. DLW of GO/LCM photoresist has shown a vigorous bubble formation. This may be due to the excessive heat generation upon rapid energy absorption of 780 nm laser energy. Compared to pure LCM photoresists, AuNR/LCM photoresists have a lower laser intensity threshold and higher critical laser scanning speed, due to the high absorption of AuNRs at 780 nm, which enhanced the photo-sensitivity of the photoresist. Therefore, a shorter printing time can be achieved for the AuNR/LCM photoresist.

Novel imaging technique for non-destructive metrology and characterization of ultraviolet-sensitive polymeric microstructures.

The negative photoresist SU-8 has attracted much research interest as a structural material for creating complex three-dimensional (3D) microstructures incorporating hidden features such as microchannels and microwells for a variety of lab-on-a-chip and biomedical applications. Achieving desired topological and dimensional accuracy in such SU-8 microstructures is crucial for most applications, but existing methods for their metrology, such as scanning electron microscopy (SEM) and optical profilometry, are not practical for non-destructive measurement of hidden features. This paper introduces an alternative imaging modality for non-destructively characterizing the features and dimensions of SU-8 microstructures by measuring their transmittance of 365 nm ultraviolet (UV) light. Here, depth profiles of SU-8 3D microstructures and thin films are determined by relating UV transmittance and the thicknesses of SU-8 samples imaged in the UV spectrum through the Beer-Lambert law applied to the images on a pixel-by-pixel basis. This technique is validated by imaging the UV transmittance of several prototype SU-8 3D microstructures, including those comprising hidden hollow subsurface features, as well as SU-8 thin-films, and verifying the measured data through SEM. These results suggest that UV transmittance imaging offers a cost-effective, non-destructive technique to quickly measure and identify SU-8 microstructures with surface and hidden subsurface features unlike existing techniques.

Strontium titanate with inverse opal structure as the photocatalysts

The microstructure of the catalyst material is one of the most important factors affecting the photocatalytic performance. In this study, inverse opal structure strontium titanate (SrTiO3, STO) materials with different pore sizes (from 75 to 123 nm) were prepared, and employed as photocatalysts in the degradation of rhodamine B (RhB) dye. The results suggest that the highest photodegradation rate of the inverse opal structure photocatalyst reaches to 88.03%, which is greater than that of the non-inverse opal structure (50.42%) due to its complex three-dimensional porous microstructure. The effect of the pore size of the inverse opal structure STO on the photocatalytic properties was investigated. As the pore size of the inverse opal microstructure decreases, the photocatalytic degradation rate increases regularly, attributing to effective capture of light with decreasing of pore size. The photocatalytic degradation mechanism of inverse opal structure with different pore sizes is discussed in this work.

Discrete element models of fracture in tooth enamel: Failure mode competition and statistical effects

Capturing how cracks initiate and propagate in tooth enamel is difficult because of the complex three-dimensional microstructure of this material. In this work we use the discrete element method (DEM) to model fracture in idealized enamel structures where the enamel rod microstructure is explicitly represented with DEM elements. The model captures the interactions of a propagating crack with the mineral rods and their interfaces, including crack deflection and penetration into the rods. We used this model to assess the effect of relative strength and stiffness between the rods and the interfaces, of the decussation angle, and of statistical distributions of defects in the mineral rods. We show that higher strength rods (smaller flaws) promote interface crack deflection and branching which increases toughness through spreading of an inelastic region. Stiffer rods increase the load carried by the rod, which ultimately decreases crack resistance. Statistical variations in rod strength were shown to have an overall negative impact on the average crack resistance. In particular, for high coefficients of variation we observed substantial nucleation of ‘daughter’ cracks far from the main crack, which steer the main crack along the weakest trajectories and decrease overall toughness. This model and results provide insights to better interpret fracture experiments in human or bovine enamel, as well as better guidelines for the design of synthetic dental and bioinspired materials.

PDMS double casting method enabled by plasma treatment and alcohol passivation

We propose a simple and efficient polydimethylsiloxane (PDMS) double casting method using plasma treatment followed by methanol or ethanol treatment. The plasma treatment oxidizes the functional groups on the surface of the PDMS mold, showing an increase in the concentration of hydroxyl functional groups (OH); subsequent exposure to the alcohols prevents adherence of the second PDMS casting. This process effectively passivates the surface of the PDMS master mold to suppress further chemical bonding. This two-step surface treatment ensures excellent double casting performance at a single micron scale resolution to yield micron level reproduction of objects featuring high aspect ratios, two-dimensional surface micropatterns, and complex three-dimensional microstructures.

Three-Dimensional Model Based Simulation of the Solid State Batteries

With the development of lithium ion battery (LIB) are recognized as a practical green option for the energy transportation and storage. Over the past decades, solid state batteries (SSB) have received the much attention among the LIB researchers, due to the development of electrolytes with high conductivity comparable to that of the liquid electrolyte. Additionally, the SSB have high energy density, non-flammability and large electrochemical window compared to the conventional liquid electrolytes. The electrolyte for SSB are classified as the oxide and sulphide. Among the solid electrolyte, the oxide electrolytes are considered to be chemically more stable whereas the sulphide electrolytes possessed relatively high ionic conductivity. With the development of the SSB, there is a need for the simulation tools in order to allow the battery engineers to explore the effects of various materials properties, geometries, etc. on the overall performances of the SSB. Simulation studies will provide an opportunity to explore the fundamental phenomena involved and the strategies to optimize the SSB performance. The objectives of this study are twofold. First is the identification of the bulk parameters of the SSB component materials. Second, the estimation of interfacial properties in SSB by utilizing the bulk parameters. In this study, mass transport phenomena and the electrochemical reactions were considered by solving the numerical equations based on the finite element method. The model used includes the diffusion of the lithium in the active material (AM), diffusion of ions in the electrolyte and the charge kinetic transfer at the electrode-electrolyte interface. Firstly, numerical simulations were performed to identify the bulk parameters of the single particle of commonly used positive AM, i.e., LixCoO2 (LCO). The results of this study have been compared with the experimental study conducted by Dokko et al. (2009). The simulated models predict global discharge characteristics that were overall in a good agreement with the experimental result as shown in Figure 1. In the second part of this study, complex three-dimensional micro-structure of the electrode (cathode) was taken into an account. For that purpose, an in-house code was used to model the composite electrode system of SSB, consisting of the idealized micro-structure, i.e., spherical, containing both the AM and solid electrolyte (SE). The simulation model assumes the transport number of the SE is unity, which is usually the case for the SE systems. Additionally, in this study, we have also taken into account the coating of the AM, which is usually done to reduce the contact resistance between the AM and the sulphide SE particles. The model predictions revealed that the concentration of lithium remain unchanged in the SE over a period of time. It is also found from the simulations that a significant concentration gradient developed among the positive AM particles at high discharge current. Reference: Dokko, N. Nakata, K. Kanamura, Journal of Power Sources, 189, (2009) 783–785 Figure 1

Highly Conductive, Photolithographically Patternable Ionogels for Flexible and Stretchable Electrochemical Devices.

An ionic conducting membrane is an essential part in various electrochemical devices including ionic actuators. To miniaturize these devices, micropatterns of ionic conducting membrane are desired. Here, we present a novel type of ionogel that can be patterned using standard photolithography and soft imprinting lithography. The ionogel is prepared in situ by UV-initiated free-radical polymerization of thiol acrylate precursors in the presence of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The resultant ionogel is very flexible with a low Young's modulus (as low as 0.23 MPa) and shows a very high ionic conductivity (up to 2.4 × 10-3 S/cm with 75 wt % ionic liquid incorporated) and has a reactive surface due to the excess thiol groups. Micropatterns of ionogel are obtained by using the thiol acrylate ionogel solution as an ionic conducting photoresist with standard photolithography. Water, a solvent immiscible with ionic liquid, is used as the photoresist developer to avoid complete removal of ionic liquid from thin micropatterns of the ionogel. By taking advantage of the reactive surface of ionogels and the photopatternability, ionogels with complex three-dimensional microstructure are developed. The surface of the ionogels can also be easily patterned using UV-assisted soft imprinting lithography. This new type of ionogels may open up for building high-performance flexible electrochemical microdevices.