Scientific article! Nanoscale transparent glass technology, 3D printing, no low temperature sintering

Have a complex3DStructural silica glass is one of the most important engineering application materials in some of the newest technological fields, including micro-optics, photonics and micro-electromechanical systems (MEMS) as well as in areas such as microfluidics and biomedicine. However, insufficient development of manufacturing technology for complex three-dimensional structured silica glasses at the micro-nano level limits their application in microsystems technology, thereby hindering major technological advancements. Existing microsystems synthesis routes typically fabricate silicon dioxide structures through carefully designed sequences of top-down processes, which involve technologies such as two-dimensional mask photolithography, thermal oxidation, evaporation, and etching. However, these processes are difficult to convert to 3D design.

Additive manufacturing technology (3DPrinting) is an efficient manufacturing method for making complex three-dimensional structures. But use3DImplementing printing technology is complex3DStructural silica glass is a difficult problem, mainly because the softening point of silica glass is1100°Cwhile the most advanced3DPrinting and casting methods still rely on the same pellet melting or sintering steps as old blowing techniques and well-established industrial processes. The latest development in two-photon polymerization3DPrinting technology (TPP) can achieve almost without constraint3DPrint. Recently, relevant publications have reported that silica glassTPPThese printing methods are based on loading particles with sacrificial polymer binders. In order to remove the binder and fuse the silica particles into a solid structure, it is necessary to1100°to1300°CThe sintering process takes place for several days under vacuum or an inert atmosphere. These temperatures are higher than the melting points of many important technical semiconductors, such as germanium, cadmium telluride, and indium phosphide, which are among the most efficient materials for solar cells, infrared optical fibers, and infrared, lasers and photodetectors, hence the importance of this approach. Applicability is very limited.

Recently, California State UniversityJ. BauerThe team proposed a method that does not require sintering and can be carried out at low temperatures3DSilica glass printing technology can realize the manufacturing of complex and transparent fused silica glass nanostructures. This technology mainly uses polyhedral oligosiloxanes functionalized with acrylates (POSSIBLE) enables sinter-free two-photon polymerization of free-form fused silica nanostructures to achieve nanostructure printing. Unlike the sacrificial adhesive mentioned above, this onePOSSIBLEThe resin itself constitutes a continuous network of silicon and oxygen molecules, which only650Transparent fused quartz can be formed at ℃. This temperature is lower than the sintering temperature required to melt discrete silica particles into a continuous mass.500°C. This work is entitled “A sinter-free, low-temperature route to 3D printing optical-quality glass at the nanoscale“The article was published inSciencesuperior.

POSSIBLEResin formulation and nanostructure construction

This article usesPOSS-Glass resin is a negative toneTPPPhotoresist consists of three parts, each with a specific set of functions: (i) 89% by weight functional acrylatePOSSIBLEmonomer,(ii) 9% by weight Trifunctional acrylic monomer,(iii) 2% by weight A–Photoinitiator of the aminoketone family.POSSIBLEThe monomer is the main component and itsPOSSIBLEThe heart of the cage constitutes a source of silicon-oxygen nanoclusters, which makesSiO2be transformed. Its acrylic functional groups are essential to achieve high performanceTPPCrucial.

However,POSSIBLEThe rigid structure of monomers often prevents the formation of fully cross-linked free-standing compounds.TPPPrinted copies. In this article, despite89% high silicon loading, but the conformational flexibility of the small addition of long-arm branched trifunctional acrylates facilitatesTPPLight cures and provides significant crack resistance elasticity. This is essential for printing structures with silica-oxygen nanoclusters tightly enough that they successfully convert to dense silica at low temperatures. In addition, the concentration of branched trifunctional acrylates makes it possible to control the viscosity of the resin. Acts as an eluent mediating the diffusion of free radicals and dissolved molecular oxygen, allowing the resin to3DPrint finely resolved features.

used in this article is a commercial messageTPP 3D ModelPrinting system. In it, the resin is deposited on a molten quartz or silicon substrate, and the printer’s magnifying glass is immersed directly into the resin. The lens focuses a high-speed pulsed laser into the resin. In the focal range, the photoinitiator molecule absorbs two photons simultaneously, causing its homogeneous fragmentation and the formation of two free radicals. These free radicals initiate the cross-linking of the monomeric acrylate groups, transforming the resin into a solid network. The three-dimensional structure is printed by scanning in the plane of the focused laser beam using a galvanometer and three-axis movement of the piezoelectric sample stage. After printing, the remaining uncured resin was dissolved in an isopropyl alcohol developing bath. performed in the air650Moderate heat treatment at ℃ converts the printed polymer pattern into a fused quartz structure. Accompanied by approx.40%Isotropic linear shrinkage, rising temperatures decompose and outgas organic compounds, and atmospheric oxygen removes remaining carbonaceous elements.3DThe resolution, structural quality, and recoverable size of printed products exceed previously reported inorganics.TPPPrinted documents. The article demonstrates the97nmSize-independent characteristics of photonic crystals composed of wood stacks, consistent with those generally reported for inorganic crystals.TPPMatch the smallest features of the structure. The paper also demonstrated the printing of novel nanolattice metamaterials composed of thousands of individual rods, smooth-shaped aspherical microlenses, and complex mesoscale microobjects, with a total size of approximately150Micron, which contains diffractive lens elements with nanoscale detail. Overall, thisPOSS-The glass process has reached a level of print quality, sophistication and coverage sizes previously only possible with polymer structures using standard organic resins.

Characterization of optical materials and applications

Complete thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mass spectrometry as well as micro-Raman spectroscopy and transmission electron microscopy (TEM), confirming that in the air only650Moderate heat treatment at ℃ successfullyPOSSIBLEThe resin is transformed into pure fused silica. The material has undergone approx.65%The total mass loss, in415°、480° and595°CThere are three mass-derived peaks associated with the three exothermic peaks in the heat flux data. These peaks correspond respectively to three consecutive reaction stages, characteristic of the thermo-oxidative degradation of highly crosslinked acrylic polymers. exist650℃ or more,TGAAndDSCNeither showed any other obvious changes, suggesting that all the organic components had completely volatilized, leaving the inorganic material behind. In general, oxidizing atmospheres accelerate the decomposition process. In a pure oxygen atmosphere, our material operates at approximately600Decomposition is completed at ℃.

The research team for this article designed3DA printing procedure that uses this material to create free-form fused silica glass micro-optical elements with excellent optical properties for use in lens systems for imaging and beam shaping. to useTPPRaised fused silica planar microlenses printed with digitally optimized aspherical profiles to correct spherical aberration. finalPOSS-Glass lens with base diameter82Micron, sagittal (subsidence) the height is15Micron, in650Processed at ℃, it exhibits pristine structural quality, with fine nanoscale contours and a smooth surface. Optical profilometry confirms its exceptional shape accuracy, with ±peak-to-trough deviation of the lens profile compared to aspherical designs175nanometer. The measured effective value of roughness is8.1nanometers, which means that the effective-to-sag ratio is0.05%. Then use1951Optical resolution measurements carried out on a US Air Force type resolution target demonstrated the excellent imaging performance of the microlens.

summary

This article proposes on the basis ofPOSS-glass resinTPP 3D ModelPrinting technology helps redefine the paradigm of free manufacturing of silica glass and overcome the fundamental limitations of particle fusion-based preparation methods. The main innovation of this approach lies in the developmentPOSSIBLEThe resin, unlike the particle-laden binder, is not sacrificial but polymerizes into a continuous network of silicon-oxygen molecules. The material therefore avoids the extreme temperatures required to sinter discrete silica particles into a continuum, simply650℃ can be converted to fused silica. with the best reportedTPPCompared to the method, the temperature is reduced by approximately500°Cwhich enables the free synthesis of silica glasses below the melting points of base materials for microsystems technology, including silver, copper, gold and aluminum. This kind ofPOSSIBLEThe potential areas of application for glass are very broad, ranging from micro-optics and photonics,MEMSfrom microfluidics and biomedical devices to fundamental research. This opens a new door for the design and preparation of silica glass with complex three-dimensional structures.

Original link:DOI: 10.1126/science.abq3037