Rapid Fabrication Research Articles

Directed Instability as a Mechanism for Fabricating Multistable Twisting Microstructure

Herein, The study of multistable structures, particularly those that can twist, has attracted significant attention in recent years. This ability to transition between multiple stable geometries of these structures paves the way for advances in diverse applications, such as morphing structures and robot actuation mechanisms. Conventional methods of designing and fabricating these structures often involve complex and resource‐intensive fabrication processes, which restrict their widespread adoption and limit their miniaturization. Here, we present a novel inflatable multistable twisting structure, based on helical folds of an elastic tube. Our fabrication approach utilizes directed mechanical instability as a method for a rapid fabrication, which is readily implemented at various length scales. We developed a theoretical model for the deformation of the bistable helical elements comprising the twisting structure, and compared the theoretical results to the experimental data. Furthermore, we demonstrate our fabrication methodology using a variety of polymers, including medical grade polymers, as well as various inner radii ranging from 5 mm to 44 μm and thicknesses of the tubes’ walls ranging from 250 μm to 19 μm.

High-Speed Electro-Optic Modulators Based on Thin-Film Lithium Niobate.

Electro-optic modulators (EOMs) are pivotal in bridging electrical and optical domains, essential for diverse applications including optical communication, microwave signal processing, sensing, and quantum technologies. However, achieving the trifecta of high-density integration, cost-effectiveness, and superior performance remains challenging within established integrated photonics platforms. Enter thin-film lithium niobate (LN), a recent standout with its inherent electro-optic (EO) efficiency, proven industrial performance, durability, and rapid fabrication advancements. This platform inherits material advantages from traditional bulk LN devices while offering a reduced footprint, wider bandwidths, and lower power requirements. Despite its recent introduction, commercial thin-film LN wafers already rival or surpass established alternatives like silicon and indium phosphide, benefitting from decades of research. In this review, we delve into the foundational principles and technical innovations driving state-of-the-art LN modulator demonstrations, exploring various methodologies, their strengths, and challenges. Furthermore, we outline pathways for further enhancing LN modulators and anticipate exciting prospects for larger-scale LN EO circuits beyond singular components. By elucidating the current landscape and future directions, we highlight the transformative potential of thin-film LN technology in advancing electro-optic modulation and integrated photonics.

A renewably sourced, circular photopolymer resin for additive manufacturing

The additive manufacturing of photopolymer resins by means of vat photopolymerization enables the rapid fabrication of bespoke 3D-printed parts. Advances in methodology have continually improved resolution and manufacturing speed, yet both the process design and resin technology have remained largely consistent since its inception in the 1980s1. Liquid resin formulations, which are composed of reactive monomers and/or oligomers containing (meth)acrylates and epoxides, rapidly photopolymerize to create crosslinked polymer networks on exposure to a light stimulus in the presence of a photoinitiator2. These resin components are mostly obtained from petroleum feedstocks, although recent progress has been made through the derivatization of renewable biomass3–6 and the introduction of hydrolytically degradable bonds7–9. However, the resulting materials are still akin to conventional crosslinked rubbers and thermosets, thus limiting the recyclability of printed parts. At present, no existing photopolymer resin can be depolymerized and directly re-used in a circular, closed-loop pathway. Here we describe a photopolymer resin platform derived entirely from renewable lipoates that can be 3D-printed into high-resolution parts, efficiently deconstructed and subsequently reprinted in a circular manner. Previous inefficiencies with methods using internal dynamic covalent bonds10–17 to recycle and reprint 3D-printed photopolymers are resolved by exchanging conventional (meth)acrylates for dynamic cyclic disulfide species in lipoates. The lipoate resin platform is highly modular, whereby the composition and network architecture can be tuned to access printed materials with varied thermal and mechanical properties that are comparable to several commercial acrylic resins.

Rapid Fabrication of Large-Grain Opal Films and Photonic Crystal Hydrogel Sensors by a Filter Paper-Enhanced Evaporation Chip.

Developing a rapid fabrication method for crack-free opal films is a significant challenge with broad applications. We developed a microfluidic platform known as the "filter paper-enhanced evaporation microfluidic chip" (FPEE-chip) for the fabrication of photonic crystal and inverse opal hydrogel (IOPH) films. The chip featured a thin channel formed by bonding double-sided adhesive poly(ethylene terephthalate) with a polymethyl methacrylate cover and a glass substrate. This channel was then filled with nanosphere colloids. The water was guided to evaporate rapidly at the surface of the filter paper, allowing the nanospheres to self-assemble and accumulate within the channel under capillary forces. Experimental results confirmed that the self-assembly method based on the FPEE-chip was a rapid platform for producing high-quality opal, with centimeter-sized opal films achievable in less than an hour. Furthermore, the filter paper altered the stress release mechanism of the opal films during drying, resulting in fewer cracks. This platform was proven capable of producing large-grain, crack-free opal films of up to 30 mm2 in size. We also fabricated crack-free IOPH pH sensors that exhibited color and size responsiveness to pH changes. The coefficient of variation of the gray color distribution for crack-free IOPH ranged from 0.03 to 0.07, which was lower than that of cracked IOPH (ranging from 0.07 to 0.14). Additionally, the grayscale peak value in 1 mm2 of the crack-free IOPH was more than twice that of the cracked IOPH at the same pH. The FPEE-chip demonstrated potential as a candidate for developing vision sensors.

Water-induced controllable deswelling strategy enabled rapid fabrication of transparent cellulose film for plastics replacement

Plastic pollution has posed significant impacts on the ecosystem. While biodegradable transparent cellulose films are considered ideal alternatives, they still grapple with issues of high energy consumption and low production efficiency. In this study, we proposed a water-induced fiber deswelling strategy to expedite the fabrication of transparent cellulose films from wood pulp. Raw cellulose fibers were firstly disintegrated into micro-sized fibers via cold alkali swelling and mild mechanical blending. Subsequently, water was introduced to govern the swelling and aggregation behavior of these treated cellulose fibers, reducing their water retention and facilitating the rapid preparation of cellulose films. By regulating the amount of water added, cellulose film can be prepared within 1 min using vacuum filtration. Furthermore, the resulting film exhibits good wet strength, surpassing most previously reported cellulose-based films, with a wet strength exceeding 30 MPa and a wet strength retention of up to 65.7 %. With these advantageous features, the cellulose film was demonstrated for packaging and fruits preservation, showing a great potential to replace conventional plastics in the packaging applications. In addition, the life cycle environmental impacts of 1.0 kg cellulose film production (cradle-to-gate system boundary) were 12.63 kg CO2-eq, 0.04 kg SO2-eq, and 397 MJ energy use.

Rapid fabrication of binder free nickel cobalt oxide electrodes with dendritic nanostructure for electrochemical energy storage applications

A rapid and facile technique to synthesize nickel cobalt oxide electrodes by photothermal treatment of mixed organometallic precursor solution is reported. Using short and intense pulses of light from a xenon flash lamp, spray coated films are converted into porous nickel cobalt oxide electrodes with dendritic nanostructure. The electrode films fabricated in a few seconds show excellent energy storage properties as supercapacitor electrodes. Specific capacitance of up to 116 Fg−1 and capacitance retention of up to 75 % were observed in samples with low mass loading. Analysis of the cyclic voltammetry (CV) curves shows that capacitance is the dominating charge storage mechanism in these films. To study the effect of varying the mass loading in electrodes, double and triple layered electrodes were also studied. In films with high mass loading, the specific capacitance of the films decreased but areal capacitance continued to increase. A high areal capacitance of up to 243 mFcm−2 is observed in films with high mass loading. CV curve analysis of high mass loading electrodes further shows that in films with higher mass loading, the charge storage mechanism is a mix of capacitance and diffusion processes. The contribution of diffusion increased with increase in the mass loading of the electrodes. This study sheds light into the mechanism of charge storage in electrodes prepared by large-scale-amenable single step process of photonic curing which could be utilized to fabricate electrodes in industrial scale.

Development and Characterization of Heparin-Containing Hydrogel/3D-Printed Scaffold Composites for Craniofacial Reconstruction.

Regeneration of cartilage and bone tissues remains challenging in tissue engineering due to their complex structures, and the need for both mechanical support and delivery of biological repair stimuli. Therefore, the goal of this study was to develop a composite scaffold platform for anatomic chondral and osteochondral repair using heparin-based hydrogels to deliver small molecules within 3D-printed porous scaffolds that provide structure, stiffness, and controlled biologic delivery. We designed a mold-injection system to combine hydrolytically degradable hydrogels and 3D-printed scaffolds that could be employed rapidly (<30min) in operating room settings (~23°C). Micro-CT analysis demonstrated the effectiveness of our injection system through homogeneously distributed hydrogel within the pores of the scaffolds. Hydrogels and composite scaffolds exhibited efficient loading (~94%) of a small positively charged heparin-binding molecule (crystal violet) with sustained release over 14days and showed high viability of encapsulated porcine chondrocytes over 7days. Compression testing demonstrated nonlinear viscoelastic behavior where tangent stiffness decreased with scaffold porosity (porous scaffold tangent stiffness: 70%: 4.9MPa, 80%: 1.5MPa, and 90%: 0.20MPa) but relaxation was not affected. Lower-porosity scaffolds (70%) showed stiffness similar to lower ranges of trabecular bone (4-8MPa) while higher-porosity scaffolds (80% and 90%) showed stiffness similar to auricular cartilage (0.16-2MPa). Ultimately, this rapid composite scaffold fabrication method may be employed in the operating room and utilized to control biologic delivery within load-bearing scaffolds.

Flash soldering of boron nitride nanosheets for all-ceramic films

The assembly of boron nitride nanosheets (BNNSs) into strong, flexible thin films capable of withstanding extreme conditions, such as high/low working temperatures and corrosive environments, holds promise for numerous applications. However, Assmebling and sintering of BNNS into dense thin film can be challenging. We report the rapid fabrication of dense BNNS all-ceramic films (BACFs) in 30 s by combining the fabrication strategies for 2D and ceramic materials. In this process, densely arranged and highly oriented BNNSs are flash soldered into a monolith achieved by precisely controlled ultrafast sintering. This fusion of BNNS leads to an ultrahigh in-plane thermal conductivity of 134.5 W·m−1·K−1. The as-prepared BACF exhibits the combined advantages of sintered ceramics (durability, stability, acid-alkali resistance) and 2D material films such as flexibility and shock resistance, which is important for practical uses. It also has excellent cooling performance, dielectric properties, and good thermal stability, which is promising for demanding thermal management applications in emerging technologies.

Micro-optics fabrication using blurred tomography

We demonstrate the fabrication of millimeter-sized optical components using tomographic volumetric additive manufacturing (VAM). By purposely blurring the writing beams through the use of a large etendue source, the layer-like artifacts called striations are eliminated enabling the rapid and direct fabrication of smooth surfaces. We call this method blurred tomography and demonstrate its capability by printing a plano–convex optical lens with comparable imaging performance to that of a commercially available glass lens. Furthermore, due to the intrinsic freeform design nature of VAM, we demonstrate the double-sided fabrication of a biconvex microlens array, and for the first time demonstrate overprinting of a lens onto an optical fiber using this printing modality. This approach to VAM will pave the way for low-cost, rapid prototyping of freeform optical components.

Downsizing nanoarchitectonics of multilayered MXenes electrocatalysts towards real time ion tracking via EQCM and electrocatalytic applications

Since their discovery, engineering two-dimensional (2D) MXene materials have attracted rapid interest in both energy storage and conversion applications. Among the several techniques being introduced for enhancing material properties, downsizing is one among the interesting approaches. Downsizing involves the deliberate scaling down of active 2D materials, such as MXenes, systematically. Although major studies are focused on the electrochemical applications of single layered MXene flakes, curiosity in evaluating the downsized multilayered MXenes for electrochemical applications motivates this project. Thus, in the current study, the multilayered bulk MXenes are sequentially stepped down to smaller multilayered fragments at definite time intervals, and subsequently the potential of this procured heterogeneous polydispersed solution are evaluated towards electrochemical applications without any further post-treatments. Real time monitoring of lithium-ion exchange in the downsized MXene materials at various time intervals was tracked using the electrochemical quartz crystal microbalance technique, where the downsized MXene system exhibited water-assisted lithium-ion transfer behavior. Increase in mass exchange was found to increase with increase in downsized MXene systems, thus making it very interesting towards ion storage applications. Further, downsized MXene electrocatalyst material delivered the lowest onset potential for hydrogen production among the set of catalysts studied. In short, this study outlines and pioneers some interesting observations regarding both energy storage and catalytic applications of multilayered downsized MXenes, thereby opening up new possibilities for facile, rapid and cost-effective material fabrication approaches.

Direct 3D printing of triple-responsive nanocomposite hydrogel microneedles for controllable drug delivery

Hydrogel microneedle patches have emerged as promising platforms for painless, minimally invasive, safe, and portable transdermal drug administration. However, the conventional mold-based fabrication processes and inherent single-functionality of such microneedles present significant hurdles to broader implementation. Herein, we have developed a novel approach utilizing a precursor solution of robust nanocomposite hydrogels to formulate photo-printable inks suitable for the direct 3D printing of high-precision, triple-responsive hydrogel microneedle patches through digital light processing (DLP) technology. The ink formulation comprises four functionally diverse monomers including 2-(dimethylamino)ethyl methacrylate, N-isopropylacrylamide, acrylic acid, and acrylamide, which were crosslinked by aluminum hydroxide nanoparticles (AH NPs) acting as both reinforcing agents and crosslinking centers. This results in the formation of a nanocomposite hydrogel characterized by exceptional mechanical strength, an essential attribute for the 3D printing of hydrogel microneeedle patches. Furthermore, this innovative 3D printing strategy facilitates facile customization of microneedle geometry and patch dimensions. As a proof-of-concept, we employed the fabricated hydrogel microneedles for transdermal delivery of bovine serum albumin (BSA). Importantly, these hydrogel microneedles displayed no cytotoxic effects and exhibited triple sensitivity to pH, temperature and glucose levels, thereby enabling more precise on-demand drug delivery. This study provides a universal method for the rapid fabrication of hydrogel microneedles with smart responsiveness for transdermal drug delivery applications.

Cellulose nanofiber-mediated manifold dynamic synergy enabling adhesive and photo-detachable hydrogel for self-powered E-skin

Self-powered skin attachable and detachable electronics are under intense development to enable the internet of everything and everyone in new and useful ways. Existing on-demand separation strategies rely on complicated pretreatments and physical properties of the adherends, achieving detachable-on-demand in a facile, rapid, and universal way remains challenging. To overcome this challenge, an ingenious cellulose nanofiber-mediated manifold dynamic synergy strategy is developed to construct a supramolecular hydrogel with both reversible tough adhesion and easy photodetachment. The cellulose nanofiber-reinforced network and the coordination between Fe ions and polymer chains endow the dynamic reconfiguration of supramolecular networks and the adhesion behavior of the hydrogel. This strategy enables the simple and rapid fabrication of strong yet reversible hydrogels with tunable toughness ((Valuemax-Valuemin)/Valuemax of up to 86%), on-demand adhesion energy ((Valuemax-Valuemin)/Valuemax of up to 93%), and stable conductivity up to 12 mS cm−1. We further extend this strategy to fabricate different cellulose nanofiber/Fe3+-based hydrogels from various biomacromolecules and petroleum polymers, and shed light on exploration of fundamental dynamic supramolecular network reconfiguration. Simultaneously, we prepare an adhesive-detachable triboelectric nanogenerator as a human-machine interface for a self-powered wireless monitoring system based on this strategy, which can acquire the real-time, self-powered monitoring, and wireless whole-body movement signal, opening up possibilities for diversifying potential applications in electronic skins and intelligent devices.

Poisson Effect‐Assisted Replication Lithography for Rapid Fabrication of Three‐Dimensional Microstructures

Demands for micro‐ and nano‐fabrication techniques have been increasing over recent decades due to their foundational importance in fields such as electronics, sensors, displays, biotechnologies, and energy technologies. Still, the rapid and efficient fabrication of complex 3D microstructures has long been a challenge due to the inherent limitations of conventional imprint lithography and the slow fabrication speed of maskless lithography systems using femtosecond lasers. This study introduces a novel lithographic replication method for the rapid replication of intricate 3D microstructures with closed‐loops by leveraging the Poisson effect‐driven lateral deformation of soft molds. Specifically, the suggested technique employs an elastomeric soft mold, engraved with negative cavity parts of the target structure separated by intentional gaps. Lateral deformation of the material allows the separated cavities to assemble for replication of target microstructure and defectless release from the soft mold. In addition to the experimental demonstrations of the proposed method using well‐known materials like polydimethysliloxane (PDMS) for the soft mold and UV‐curable polyurethane acrylate (PUA) for replication, essential considerations such as material selection and master mold design are discussed. The presented method not only broadens the capabilities of imprint lithographic techniques but also holds promise for the large scale, continuous fabrication of complex 3D microstructures.

Hybrid Transfer Printing of Liquid Metals and Allied Inks for Rapid Fabrication of Multifunctional Soft Electronics.

The newly emerging liquid metal flexible electronics are gaining increasing applications over the world due to their outstanding adaptability and printability. Here, we proposed a generalized purpose thermo-activated hybrid transfer printing method for the rapid fabrication of multifunctional soft electronics, which can significantly reduce the difficulty facing existing technologies. This printing involves two delivery and deposition processes of liquid metals and the allied inks (toners) based on their adhesion selection mechanisms. Through developing office supplies, the laser printer could directly print toner masks on soft substrates, such as polydimethylsiloxane film. The heating plate was applied to remove the toner sacrificial mask after rolling liquid metal inks, resulting in retaining the liquid metal circuits on the target substrate. For illustration, diverse materials and inks are adapted to the strategy of constructing flexible electronics. Particularly, colorful circuits, flexible heaters, transparent circuitry, and soft programmable light-emitting diode array displays with multilayer circuits have been fabricated and tested. This general and easily accessible method allows for the rapid acquisition of user-designed soft electronics and is expected to promote the widespread use of flexible electronics in e-skin, sensing, displays, etc.

Enhanced Pool Boiling Heat Transfer with Porous Ti-6Al-4V-Coatings Produced by Cold Spray Metal Additive Manufacturing

In advancing industrial heat transfer mechanisms, surface coatings offer significant potential. This research elucidates the efficacy of the metal additive manufacturing Cold Spray deposition technique for producing enhanced boiling surfaces, specifically focusing on Ti-6Al-4V (Ti64) coatings on Aluminium substrates. This offers a rapid and low-cost fabrication method for producing lightweight enhanced boiling surfaces. The Cold Spray method is typically used to create dense metal deposits. Here, the process has been specially tuned to create highly inhomogeneous honeycomb-type porous Ti64 coatings. Critical Cold Spray deposition parameters, such as particle velocity, preheat temperature, and deposition rate have been identified to create repeatable porous coatings, with thicknesses of up to 3.0 mm achievable. Following deposition, several samples were subjected to systematic boiling heat transfer tests in a purpose-built pool boiling apparatus. Boiling curves were generated for the augmented Cold Spray surfaces as well as a bare surface, with the latter acting as a baseline to which enhancement levels were assessed. Initial data analysis shows that some of the tested surfaces exhibit a notable increase in boiling heat transfer coefficient and Critical Heat Flux (CHF). This enhancement is potentially attributed to increased surface area, increased nucleation site density, capillary wicking, and mitigation of lateral bubble coalescence, though excessive coating thickness may degrade heat transfer. In summary, the novel Ti64 surface structures developed using the Cold Spray deposition technique exhibits high potential for industries necessitating superior boiling heat transfer performance. Importantly, the manufacturing process is industrially scalable, offering the capacity to rapidly coat large areas at low cost compared with subtractive manufacturing other metal additive manufacturing methods.

Rapid and Green Fabrication of Nanozyme with Geminal CuN3O Configuration for Efficient Catecholase-Mimicking.

Fabrication of nanozyme with catecholase-like catalytic activity faces the great challenge of merging outstanding activity with low cost as well as simple, rapid, and low-energy-consumed production, restricting its industrial applications. Herein, an inexpensive yet robust nanozyme (i.e., DT-Cu) via simple one-step coordination between diaminotriazole (DT) and CuSO4 within 1h in water at room temperature is constructed. The asymmetric dicopper site with CuN3O configuration for each copper as well as Cu─O bond length of ≈1.83 Å and Cu···Cu distance of ≈3.5 Å in DT-Cu resemble those in catechol oxidase (CO), which ensure its prominent intrinsic activity, outperforming most CO-mimicking nanozymes and artificial homogeneous catalysts. The use of inexpensive DT/CuSO4 in this one-pot strategy endows DT-Cu with only ≈20% cost of natural CO per activity unit. During catalysis, O2 experienced a 4e-dominated reduction process accompanied by the formation of 1O2 and H2O2 intermediates and the product of H2O. Benefiting from the low cost as well as the distinctive structure and superior intrinsic activity, DT-Cu presents potential applications ranging from biocatalysis to analytical detection of biomolecules such as epinephrine and beyond.

Challenges faced with 3D-printed electrochemical sensors in analytical applications.

Prototyping analytical devices with three-dimensional (3D) printing techniques is becoming common in research laboratories. The attractiveness is associated with printers' price reduction and the possibility of creating customized objects that could form complete analytical systems. Even though 3D printing enables the rapid fabrication of electrochemical sensors, its wider adoption by research laboratories is hindered by the lack of reference material and the high "entry barrier" to the field, manifested by the need to learn how to use 3D design software and operate the printers. This review article provides insights into fused deposition modeling 3D printing, discussing key challenges in producing electrochemical sensors using currently available extrusion tools, which include desktop 3D printers and 3D printing pens. Further, we discuss the electrode processing steps, including designing, printing conditions, and post-treatment steps. Finally, this work shed some light on the current applications of such electrochemical devices that can be a reference material for new research involving 3D printing.

Rapid fabrication of mechanical-improved hydroxyapatite scaffolds from the microwave sintering with homogenous incorporated nanosilver particles

In this study, the optimization of the dual-frequency microwave sintering furnace in the replica method was investigated for the rapid synthesis of Porous hydroxyapatite scaffolds (PHS). It was found that by controlling the microwave sintering condition, it is possible to produce PHS with promising abilities for bone tissue engineering applications.

Facile and rapid fabrication of a novel 3D-printable, visible light-crosslinkable and bioactive polythiourethane for large-to-massive rotator cuff tendon repair

Facile and rapid 3D fabrication of strong, bioactive materials can address challenges that impede repair of large-to-massive rotator cuff tears including personalized grafts, limited mechanical support, and inadequate tissue regeneration. Herein, we developed a facile and rapid methodology that generates visible light-crosslinkable polythiourethane (PHT) pre-polymer resin (∼30 min at room temperature), yielding 3D-printable scaffolds with tendon-like mechanical attributes capable of delivering tenogenic bioactive factors. Ex vivo characterization confirmed successful fabrication, robust human supraspinatus tendon (SST)-like tensile properties (strength: 23 MPa, modulus: 459 MPa, at least 10,000 physiological loading cycles without failure), excellent suture retention (8.62-fold lower than acellular dermal matrix (ADM)-based clinical graft), slow degradation, and controlled release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-β3 (TGF-β3). In vitro studies showed cytocompatibility and growth factor-mediated tenogenic-like differentiation of mesenchymal stem cells. In vivo studies demonstrated biocompatibility (3-week mouse subcutaneous implantation) and ability of growth factor-containing scaffolds to notably regenerate at least 1-cm of tendon with native-like biomechanical attributes as uninjured shoulder (8-week, large-to-massive 1-cm gap rabbit rotator cuff injury). This study demonstrates use of a 3D-printable, strong, and bioactive material to provide mechanical support and pro-regenerative cues for challenging injuries such as large-to-massive rotator cuff tears.

Bio-inspired fabrication of non-iridescent structural color coatings with excellent colorfastness for rapid and large-scale colorization of textile

Structural color in nature provides a new strategy for eco-friendly colorization. Biomimetic construction of amorphous photonic crystals (APCs) on the substrate surface can form a specific non-iridescent structural color, which can be widely used in textile, paint and other fields. However, the APCs structural color has the shortcomings of dim color and poor colorfastness, which restrict the industrial application. In this study, base on the structural design of APCs building blocks, a novel copolymer containing reactive epoxy groups of poly (styrene-co-glycidyl methacrylate) (P(St-co-GMA)) was synthesized, which was used for fabricating APCs structural color by rapid spray coating method. P(St-co-GMA) nanospheres with different particle diameters can be self-assembled into APCs showing different crack-free structural colors. This research reports for the first time that the polymer nanospheres with two different particle diameters were synthesized by one-pot polymerization to enhance the color brightness of structural color. P(St-co-GMA) nanospheres structural colorized fabrics showed excellent colorfastness, flexibility and air permeability. This research promotes the industrial application of structural color for the rapid larger-scale fabrication of APCs with excellent colorfastness on substrates through the synthesis of polymer nanospheres with reactive epoxy groups.