Multifunctionality of Additively Manufactured Kelvin Foam for Electromagnetic Wave Absorption and Load Bearing.

Rationally engineered porous structures enable lightweight broadband electromagnetic (EM) wave absorbers for countering radar signals or mitigating EM interference between multiple components. However, the scalability of such structures has been hindered by their limited mechanical properties resulting from low density. Herein, an additively manufactured Kelvin foam-based EM wave absorber (KF-EMA) is reported that exhibits multifunctionality, namely EM wave absorption and light-weighted load-bearing structures with constant relative stiffness made possible using bending-dominated lattice structures. Based on tuning design parameters, such as the backbone structures and constituent materials, the proposed KF-EMA features a multilayered 3D-printed design with geometrically optimized KF structures made of carbon black-based backbone composites. The developed KF-EMA demonstrated an absorbance greater than 90% at frequencies ranging from 5.8 to 18 GHz (average EM wave absorption rates of 95.89% and maximum of 99.1% at 15.8 GHz), while the low-density structures of the absorber (≈200 kg m-3 ) still maintained a compression index between the stiffness and relative density (n = 2) under compression. The design strategy paves the way for using metamaterials as mechanically reinforced EM wave absorbers that enable multifunctionality by optimizing unit-cell parameters through a single and low-density structure.

Simultaneous electric production and sizing of emulsion droplets in microfluidics.

Microscale emulsions are widely used in fundamental and applied sciences. To expand their utilization, various methods have been developed for manipulating and measuring the physical properties of fabricated emulsions inside microchannels. Herein, we present an electric emulsification platform that can produce emulsions and simultaneously detect their physical properties (size and production speed). The characterization of the emulsion properties during the fabrication process will broaden the application fields for microscale emulsions because it can avoid time-consuming post image processing and simplify the emulsification platform. To accomplish this, a "bottleneck" channel is implanted between two reservoirs of immiscible fluids (continuous and dispersion phases). This channel can not only confine one fluid within the other when the electric field is on, resulting in emulsification via electrohydrodynamically induced Rayleigh instability, but also act as a resistive pulse sensor (RPS). The fluctuation of the liquid/liquid interface during emulsification induces the fluctuation of the electric resistance in the bottleneck channel, as the two fluid phases have different electrical conductivities. With this simple but dual-functional channel, the emulsion size (radius of 5-10 µm) and production speed (7-12 Hz) can be controlled by adjusting the electric field and the channel-neck geometry. Additionally, the properties can be measured using the RPS; the data obtained through the RPS exhibit high correlations with the validated data obtained using a high-speed camera and microscopy (>95%). The proposed buffer-less electric emulsification with the embedded RPS is a simple and cost-effective emulsion production method that allows real-time emulsion characterization with a limited sample volume.

Scalable Synthesis of Triple-Core-Shell Nanostructures of TiO2 @MnO2 @C for High Performance Supercapacitors Using Structure-Guided Combustion Waves.

Core-shell nanostructures of metal oxides and carbon-based materials have emerged as outstanding electrode materials for supercapacitors and batteries. However, their synthesis requires complex procedures that incur high costs and long processing times. Herein, a new route is proposed for synthesizing triple-core-shell nanoparticles of TiO2 @MnO2 @C using structure-guided combustion waves (SGCWs), which originate from incomplete combustion inside chemical-fuel-wrapped nanostructures, and their application in supercapacitor electrodes. SGCWs transform TiO2 to TiO2 @C and TiO2 @MnO2 to TiO2 @MnO2 @C via the incompletely combusted carbonaceous fuels under an open-air atmosphere, in seconds. The synthesized carbon layers act as templates for MnO2 shells in TiO2 @C and organic shells of TiO2 @MnO2 @C. The TiO2 @MnO2 @C-based electrodes exhibit a greater specific capacitance (488 F g-1 at 5 mV s-1 ) and capacitance retention (97.4% after 10 000 cycles at 1.0 V s-1 ), while the absence of MnO2 and carbon shells reveals a severe degradation in the specific capacitance and capacitance retention. Because the core-TiO2 nanoparticles and carbon shell prevent the deformation of the inner and outer sides of the MnO2 shell, the nanostructures of the TiO2 @MnO2 @C are preserved despite the long-term cycling, giving the superior performance. This SGCW-driven fabrication enables the scalable synthesis of multiple-core-shell structures applicable to diverse electrochemical applications.

Nanopore Sensing in Aqueous Two-Phase System: Simultaneous Enhancement of Signal and Translocation Time via Conformal Coating.

Nanofluidic resistive pulse sensing (RPS) has been extensively used to measure the size, concentration, and surface charge of nanoparticles in electrically conducting solutions. Although various methods have been explored for improving detection performances, intrinsic problems including the extremely low particle-to-pore volume ratio (<0.01%) and fast nanoparticle translocation (10-1000 µs) still induce difficulties in detection, such as low signal magnitudes and short translocation times. Herein, we present an aqueous two-phase system (ATPS) in a nanofluidic RPS for amplifying translocation signals and decreasing translocation speeds simultaneously. Two immiscible aqueous liquids build a liquid-liquid interface inside nanopores. As particles translocate from a high-affinity liquid phase into a lower-affinity one, the high-affinity liquid forms a conformal coating on the particles, which increases the effective particle size and amplifies the current-blockage signal. The translocation time is also increased, as the ATPS interface impedes the particle translocation. For 20 nm particles, 7.92-fold and 5.82-fold enhancements of signal magnitude and translocation time can be achieved. To our knowledge, this is the first attempt to improve nanofluidic RPS by treating an interface of solution reservoirs for manipulating target particles rather than nanopores. This direct particle manipulation allows us to solve the two intrinsic problems all at once.

Thermoelectric-pyroelectric hybrid energy generation from thermopower waves in core-shell structured carbon nanotube-PZT nanocomposites.

There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z0.5-T0.5)) composites for the first time. Conventional TWs use only charge carrier transport driven by the temperature gradient along the core materials to produce voltage. In this study, a core-shell structure of CNTs-PZTs was prepared to utilize both the temperature gradient along the core material (thermoelectrics) and the dynamic change in the temperature of the shell structure (pyroelectrics) induced by TWs. The dual mechanism of energy generation in CNT-PZT composites amplified the average peak and duration of the voltage up to 403 mV and 612 ms, respectively, by a factor of 2 and 60 times those for the composites without a PZT layer. Furthermore, dynamic voltage measurements and structural analysis in repetitive TWs confirmed that CNT-PZT composites maintain the original performance in multiple TWs, which improves the reusability of materials. The advanced TWs obtained by the application of a PZT layer as a pyroelectric material contributes to the extension of the usable energy portion as well as the development of TW-based operating devices.

Phase Transformations of Cobalt Oxides in CoxOy-ZnO Multipod Nanostructures via Combustion from Thermopower Waves.

The study of combustion at the interfaces of materials and chemical fuels has led to developments in diverse fields such as materials chemistry and energy conversion. Recently, it has been suggested that thermopower waves can utilize chemical-thermal-electrical-energy conversion in hybrid structures comprising nanomaterials and combustible fuels to produce enhanced combustion waves with concomitant voltage generation. In this study, this is the first time that the direct phase transformation of Co-doped ZnO via instant combustion waves and its applications to thermopower waves is presented. It is demonstrated that the chemical combustion waves at the surfaces of Co3O4-ZnO multipod nanostructures (deep brown in color) enable direct phase transformations to newly formed CoO-ZnO(1-x) nanoparticles (olive green in color). The oxygen molecules are released from Co3O4-ZnO to CoO-ZnO(1-x) under high-temperature conditions in the reaction front regime in combustion, whereas the CoO-ZnO multipod nanoparticles do not undergo any transformations and thus do not experience any color change. This oxygen-release mechanism is applicable to thermopower waves, enhances the self-propagating combustion velocity, and forms lattice defects that interrupt the charge-carrier movements inside the nanostructures. The chemical transformation and corresponding energy transport observed in this study can contribute to diverse potential applications, including direct-combustion synthesis and energy conversion.

Voltage amplification of thermopower waves via current crowding at high resistances in self-propagating combustion waves.

Combustion wave propagation in micro/nanostructured materials generates a chemical-thermal-electrical energy conversion, which enables the creation of an unusual source of electrical energy, called a thermopower wave. In this paper, we report that high electrical resistance regimes would significantly amplify the output voltage of thermopower waves, because the current crowding creates a narrow path for charge carrier transport. We show that the structurally defective regions in the hybrid composites of chemical fuels and carbon nanotube (CNT) arrays determine both the resistance levels of the hybrid composites and the corresponding output voltage of thermopower waves. A sudden acceleration of the crowded charges would be induced by the moving reaction front of the combustion wave when the supplied driving force overcomes the potential barrier to cause charge carrier transport over the defective region. This property is investigated experimentally for the locally manipulated defective areas using diverse methods. In this study, thermopower waves in CNT-based hybrid composites are able to control the peak voltages in the range of 10-1000 mV by manipulating the resistance from 10 Ω to 100 kΩ. This controllable voltage generation from thermopower waves may enable applications using the combustion waves in micro/nanostructured materials and better understanding of the underlying physics.

Effects of chemical fuel composition on energy generation from thermopower waves.

Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ∼2 V and an average peak specific power as high as 15 kW kg(-1) were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s(-1) and 157 mV, while they were 2 cm s(-1) and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H(+) and Na(+) ions, as well as the formation of fiber-like structures, because of benzene π stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source.

Mechanical metamaterials as broadband electromagnetic wave absorbers: investigating relationships between geometrical parameters and electromagnetic response.

The utilization of low-density and robust mechanical metamaterials rises as a promising solution for multifunctional electromagnetic wave absorbers due to their structured porous structures, which facilitates impedance matching and structural absorption. However, the various geometrical parameters involved in constructing these metamaterials affect their electromagnetic response, necessitating a comprehensive understanding of underlying absorbing mechanisms. Through experimentally validated numerical analysis, this study delves into the influence of geometrical factors on the electromagnetic response of representative low-density, high strength mechanical metamaterials, namely octet-truss and octet-foam. By juxtaposing electromagnetic response under varying volume fractions, cell lengths, and multilayer configurations of octet-truss and octet-foam, distinct absorption mechanisms emerge as geometrical parameters evolve. These mechanisms encompass diminished reflection owing to porous structures, effective medium approximations within subwavelength limits, and transmission-driven or reflection-driven phenomena originating from the interplay of open- and closed-cell structures. Through analyses on these mechanical metamaterials, we demonstrate the viability of employing them as tunable yet scalable structures that are lightweight, robust, and broadband electromagnetic wave absorption.

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption.

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH3), respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation: k2,AMP/C3 = 7.702 x 10(6) exp (-2248.03/T). A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.

Evaluation of accuracy of 3-dimensional printed dental models in reproducing intermaxillary relational measurements: Based on inter-operator differences.

OBJECTIVE: Although, digital models have recently been used in orthodontic clinics, physical models are still needed for a multitude of reasons. The purpose of this study was to assess whether the printed models can replace the plaster models by evaluating their accuracy in reproducing intermaxillary relationships and by appraising the clinicians' ability to measure the printed models. METHODS: Twenty sets of patients' plaster models with well-established occlusal relationships were selected. Models were scanned using an intraoral scanner (Trios 3, 3Shape Dental System) by a single operator. Printed models were made with ZMD-1000B light-curing resin using the stereolithography method 3-dimensional printer. Validity, reliability, and reproducibility were evaluated using measurements obtained by three operators. RESULTS: In evaluation of validity, all items showed no significant differences between measurements taken from plaster and printed models. In evaluation for reliability, significant differences were found in the distance between the gingival zeniths of #23-#33 (DZL_3) for the plaster models and at #17-#43 (DZCM_1) for the printed models. In evaluation for reproducibility, the plaster models showed significant differences between operators at midline, and printed models showed significant differences at 7 measurements including #17-#47 (DZR_7). CONCLUSIONS: The validity and reliability of intermaxillary relationships as determined by the printed model were clinically acceptable, but the evaluation of reproducibility revealed significant inter-operator differences. To use printed models as substitutes for plaster models, additional studies on their accuracies in measuring intermaxillary relationship are required.

Precisely Tunable Synthesis of Binder-Free Cobalt Oxide-Based Li-Ion Battery Anode Using Scalable Electrothermal Waves.

Binder-free transition metal oxide-based anodes for lithium-ion batteries (LIBs), having high capacity and abundance, have received considerable attention. However, their low conductivity and unstable charge-discharge cycles must be addressed, and scalable fabrication routes for binder-free design with optimal phase tuning are necessary. Herein, we report a precisely tunable synthesis of binder-free cobalt oxide-based LIB anodes using scalable electrothermal waves. Needle-like nanoarrays of cobalt hydroxide on nickel foams are prepared as precursors, and Joule-heating-driven electrothermal waves passing through the metal foams cause transition to cobalt oxides with preserved structures and adjustable phase tuning of grains and oxygen vacancies. The rapid heating-cooling environment using electrothermal waves causes extreme input thermal energy over the activation energy of phase transitions and metastable phase trapping. This programmable route completes the selective grain characteristics and vacancy concentrations. The electrothermally tuned binder-free LIB anodes employing the CoO/Co3O4@Ni foam-based electrodes exhibit a high-rate capacity (3.7 mAh cm-2) at 2.4 mA cm-2 for 70 charge-discharge cycles. Accumulated electrothermal waves from multiple cycles broaden the tunable ranges of the morphological and chemical transitions causing rapid screening of the optimal phases for LIB anodes. This phase-tuning strategy will inspire precise yet efficient synthesis routes for diverse binder-free electrodes and catalysts.

Electrothermally Driven Nucleation Energy Control of Defective Carbon and Nickel-Cobalt Oxide-Based Electrodes.

Multielement metal/metal oxides/carbon-based support hybrids are promising candidates for high-performance electrodes. However, conventional solid-state synthesis utilizing slow heating-cooling rates is limited by discrepancies in their phase transition temperatures. Herein, we report a rational strategy to control the nucleation energy of defective carbon fibers (DCFs) and Ni-Co-oxide-based electrodes capable of electrochemical activation using electrothermal waves (ETWs). The ETWs, triggered by Joule heating passing through CFs and Ni-Co precursors, induce programmable high-temperature processes via adjustable input powers and durations. The first ETW (∼1500 °C) fabricates the presculpted DCFs, while the second ETW (∼600 °C) directly synthesizes NiCo2O4 spinel nanoparticles on the DCFs. Predesigning DCFs through the Gibbs free energy theory enables tunable control of nucleation energy and solution compatibility with Ni-Co precursors, allowing the morphological and compositional design of the optimal NiCo2O4@DCFs hybrids. Furthermore, they are electrochemically activated to change the morphologies and oxidation states of Ni-Co to more stable wrinkled structures strongly anchored to carbon supports and Ni-Co cations with low oxidation numbers. The activated NiCo2O4@DCFs electrodes exhibit outstanding specific capacitance and long-term cyclic stability (∼1925 F g-1 and ∼115-123% for 20 000 cycles). The ETWs offer a facile yet precise method to predesign carbon supports and subsequently synthesize hybrid electrodes.

Skin-Inspired Thermometer Enabling Contact-Independent Temperature Sensation via a Seebeck-Resistive Bimodal System.

Tactile sensation is a powerful method for probing the temperature of an arbitrary object due to its intuitive operating mechanism. However, the disruptive interface commonly formed between the thermometer and the object gives rise to thermal contact resistance, which is the primary source of measurement inaccuracy. Here, we develop a bioinspired bimodal temperature sensor exhibiting robust measurement accuracy by precisely decoupling contact resistance from the associated thermal circuit. In our sensors, a micropatterned resistive thermometer is placed underneath a thermoelectric heat fluxmeter, which resembles thermoreceptors located in human biomembranes. The object temperature is probed by modulating the thermometer temperature within the sensor system and precisely extrapolating the zero-heat flux point of the Seebeck voltage developed across the fluxmeter. At this zero-heat flux point, the object and thermometer temperatures coincide with each other regardless of the contact resistance formed at the fluxmeter-object interface. An experimental study shows that our sensors display excellent measurement accuracy within ∼0.5 K over a wide range of contact resistance values. Our work opens up new avenues for highly sensitive tactile thermal sensation in thermal haptics, medical devices, and robotics if combined with flexible devices.

Dynamics of simultaneous, single ion transport through two single-walled carbon nanotubes: observation of a three-state system.

The ability to actively manipulate and transport single molecules in solution has the potential to revolutionize chemical synthesis and catalysis. In previous work, we developed a nanopore platform using the interior of a single-walled carbon nanotube (diameter = 1.5 nm) for the Coulter detection of single cations of Li(+), K(+), and Na(+). We demonstrate that as a result of their fabrication, such systems have electrostatic barriers present at their ends that are generally asymmetric, allowing for the trapping of ions. We show that above this threshold bias, traversing the nanopore end is not rate-limiting and that the pore-blocking behavior of two parallel nanotubes follows an idealized Markov process with the electrical potential. Such nanopores may allow for high-throughput linear processing of molecules as new catalysts and separation devices.

Chemically driven carbon-nanotube-guided thermopower waves.

Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. Herein, such waves are realized using a 7-nm cyclotrimethylene trinitramine annular shell around a multiwalled carbon nanotube and are amplified by more than 10(4) times the bulk value, propagating faster than 2 m s(-1), with an effective thermal conductivity of 1.28+/-0.2 kW m(-1) K(-1) at 2,860 K. This wave produces a concomitant electrical pulse of disproportionately high specific power, as large as 7 kW kg(-1), which we identify as a thermopower wave. Thermally excited carriers flow in the direction of the propagating reaction with a specific power that scales inversely with system size. The reaction also evolves an anisotropic pressure wave of high total impulse per mass (300 N s kg(-1)). Such waves of high power density may find uses as unique energy sources.

Effects of Insertion of Ag Mid-Layers on Laser Direct Ablation of Transparent Conductive ITO/Ag/ITO Multilayers: Role of Effective Absorption and Focusing of Photothermal Energy.

From the viewpoint of the device performance, the fabrication and patterning of oxide-metal-oxide (OMO) multilayers (MLs) as transparent conductive oxide electrodes with a high figure of merit have been extensively investigated for diverse optoelectronic and energy device applications, although the issues of their general concerns about possible shortcomings, such as a more complicated fabrication process with increasing cost, still remain. However, the underlying mechanism by which a thin metal mid-layer affects the overall performance of prepatterned OMO ML electrodes has not been fully elucidated. In this study, indium tin oxide (ITO)/silver (Ag)/ITO MLs are fabricated using an in-line sputtering method for different Ag thicknesses on glass substrates. Subsequently, a Q-switched diode-pumped neodymium-doped yttrium vanadate (Nd:YVO4, λ = 1064 nm) laser is employed for the direct ablation of the ITO/Ag/ITO ML films to pattern ITO/Ag/ITO ML electrodes. Analysis of the laser-patterned results indicate that the ITO/Ag/ITO ML films exhibit wider ablation widths and lower ablation thresholds than ITO single layer (SL) films. However, the dependence of Ag thickness on the laser patterning results of the ITO/Ag/ITO MLs is not observed, despite the difference in their absorption coefficients. The results show that the laser direct patterning of ITO/Ag/ITO MLs is primarily affected by rapid thermal heating, melting, and vaporization of the inserted Ag mid-layer, which has considerably higher thermal conductivity and absorption coefficients than the ITO layers. Simulation reveals the importance of the Ag mid-layer in the effective absorption and focusing of photothermal energy, thereby supporting the experimental observations. The laser-patterned ITO/Ag/ITO ML electrodes indicate a comparable optical transmittance, a higher electrical current density, and a lower resistance compared with the ITO SL electrode.

Understanding of the Mechanism for Laser Ablation-Assisted Patterning of Graphene/ITO Double Layers: Role of Effective Thermal Energy Transfer.

Demand for the fabrication of high-performance, transparent electronic devices with improved electronic and mechanical properties is significantly increasing for various applications. In this context, it is essential to develop highly transparent and conductive electrodes for the realization of such devices. To this end, in this work, a chemical vapor deposition (CVD)-grown graphene was transferred to both glass and polyethylene terephthalate (PET) substrates that had been pre-coated with an indium tin oxide (ITO) layer and then subsequently patterned by using a laser-ablation method for a low-cost, simple, and high-throughput process. A comparison of the results of the laser ablation of such a graphene/ITO double layer with those of the ITO single-layered films reveals that a larger amount of effective thermal energy of the laser used is transferred in the lateral direction along the graphene upper layer in the graphene/ITO double-layered structure, attributable to the high thermal conductivity of graphene. The transferred thermal energy is expected to melt and evaporate the lower ITO layer at a relatively lower threshold energy of laser ablation. The transient analysis of the temperature profiles indicates that the graphene layers can act as both an effective thermal diffuser and converter for the planar heat transfer. Raman spectroscopy was used to investigate the graphite peak on the ITO layer where the graphene upper layer was selectively removed because of the incomplete heating and removal process for the ITO layer by the laterally transferred effective thermal energy of the laser beam. Our approach could have broad implications for designing highly transparent and conductive electrodes as well as a new way of nanoscale patterning for other optoelectronic-device applications using laser-ablation methods.

Removal characteristics of CO2 using aqueous MEA/AMP solutions in the absorption and regeneration process.

The carbon dioxide (CO2) removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine (MEA) + 2-amino-2-methyl-1-propanol (AMP) solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA + AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA + 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA (0.41 mol CO2/mol amine). Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.

Scalable fabrication of nanopores in membranes via thermal annealing of Au nanoparticles.

Nanopores are promising candidates for versatile sensing of micro- and nanomaterials. However, the fabrication of isolated nanopores with optimal dimensions and distributions requires complex processes that involve the use of high-cost equipment. Herein, we report a scalable fabrication of isolated conical nanopores with adjustable dimensions and distribution densities on a Si3N4 membrane via thermal annealing of Au nanoparticles (AuNPs). The AuNP-dispersed solution was dropped and evaporated on the membrane, while the pH value and concentration of AuNPs controlled the zeta potential difference and the distribution density of the attached AuNPs. The optimized thermal annealing directly fabricated conical nanopores at the positions of the AuNPs because of the quasi-liquid state of the AuNPs and their interaction with the Si3N4 lattices. The 50, 100, and 200 nm AuNPs enabled one-step fabrication of 8-, 26-, and 63 nm nanopores, while the inter-distances and distribution densities were controllable over the membrane. The physicochemical analyses elucidated the underlying mechanisms of direct nanopore formation, and the precise adjustment of thermal annealing developed three unique nanopores that differently interacted with the AuNPs: (1) Au-residue-embedded nanopores, (2) isolated nanopores, and (3) nanopores with the remaining Au droplet. The AuNPs-driven fabrication of versatile nanopore membranes enables new applications for sensing and transporting small-scale materials.