Rapid High Resolution Visible Light 3D Printing

10.26434/chemrxiv.12644126 ◽

2020 ◽

Author(s):

Dowon Ahn ◽

Lynn Stevens ◽

Kevin Zhou ◽

Zachariah Page

Keyword(s):

High Resolution ◽

3D Printing ◽

Visible Light ◽

Mechanical Performance ◽

Screening Method ◽

Reaction Times ◽

High Energy ◽

Solid Objects ◽

Soft Objects ◽

Visible Wavelengths

Light-driven 3D printing to convert liquid resins into solid objects (i.e., photocuring) has traditionally been dominated by engineering disciplines, yielding the fastest build speeds and highest resolution of any additive manufacturing process. However, the reliance on high energy UV/violet light derived from decades of photolithography research, limits the materials scope due to degradation and attenuation (e.g., absorption and/or scattering). Chemical innovation to shift the spectrum into more mild and tunable visible wavelengths promises to improve compatibility and expand the repertoire of accessible objects, including those containing biological compounds and multi-material structures. Photochemistry at these longer wavelengths currently suffers from slow reaction times precluding its utility. Herein, novel panchromatic photopolymer resins were developed and applied for the first time to realize rapid high resolution visible light 3D printing. The combination of electron deficient iodonium and rich borate co-initiators were critical to overcoming the speed-limited photocuring with visible light. Furthermore, azo-dyes were identified as vital resin components to confine curing to irradiation zones, improving spatial resolution. A unique screening method was used to streamline optimization (e.g., exposure time and azo-dye loading) and correlate resin composition to resolution, cure rate, and mechanical performance. Ultimately, a versatile and general visible light-based printing method was shown to afford 1) stiff and soft objects with feature sizes < 100 μm, 2) build speeds up to 45 mm/h, and 3) mechanical isotropy, rivaling modern UV-based 3D printing technology and providing a foundation from which bio- and composite-printing can emerge.

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Additives for Ambient 3D Printing with Visible Light

10.26434/chemrxiv.14390828.v1 ◽

2021 ◽

Author(s):

Dowon Ahn ◽

Lynn Stevens ◽

Kevin Zhou ◽

Zachariah Page

Keyword(s):

3D Printing ◽

Visible Light ◽

Reaction Times ◽

High Energy ◽

Energy Methods ◽

Mechanical Responses ◽

Violet Light ◽

Acrylic Resins ◽

Printing Processes ◽

Made In

With 3D printing we desire to be “limited only by our imagination”, and although remarkable advancements have been made in recent years the scope of printable materials remains narrow compared to other forms of manufacturing. Light-driven polymerization methods for 3D printing are particularly attractive due to unparalleled speed and resolution, yet the reliance on high energy UV/violet light in contemporary processes limits the number of compatible materials due to pervasive absorption, scattering, and degradation at these short wavelengths. Such issues can be addressed with visible light photopolymerizations. However, these lower-energy methods often suffer from slow reaction times and sensitivity to oxygen, precluding their utility in 3D printing processes that require rapid hardening (curing) to maximize build speed and resolution. Herein, multifunctional thiols are identified as simple additives to enable rapid high resolution visible light 3D printing under ambient (atmospheric O2) conditions that rival modern UV/violet-based technology. The present process is universal, providing access to commercially relevant acrylic resins with a range of disparate mechanical responses from strong and stiff to soft and extensible. Pushing forward, the insight presented within this study will inform the development of next generation 3D printing materials, such as multicomponent hydrogels and composites.

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Additives for Ambient 3D Printing with Visible Light

10.26434/chemrxiv.14390828 ◽

2021 ◽

Author(s):

Dowon Ahn ◽

Lynn Stevens ◽

Kevin Zhou ◽

Zachariah Page

Keyword(s):

3D Printing ◽

Visible Light ◽

Reaction Times ◽

High Energy ◽

Energy Methods ◽

Mechanical Responses ◽

Violet Light ◽

Acrylic Resins ◽

Printing Processes ◽

Made In

With 3D printing we desire to be “limited only by our imagination”, and although remarkable advancements have been made in recent years the scope of printable materials remains narrow compared to other forms of manufacturing. Light-driven polymerization methods for 3D printing are particularly attractive due to unparalleled speed and resolution, yet the reliance on high energy UV/violet light in contemporary processes limits the number of compatible materials due to pervasive absorption, scattering, and degradation at these short wavelengths. Such issues can be addressed with visible light photopolymerizations. However, these lower-energy methods often suffer from slow reaction times and sensitivity to oxygen, precluding their utility in 3D printing processes that require rapid hardening (curing) to maximize build speed and resolution. Herein, multifunctional thiols are identified as simple additives to enable rapid high resolution visible light 3D printing under ambient (atmospheric O2) conditions that rival modern UV/violet-based technology. The present process is universal, providing access to commercially relevant acrylic resins with a range of disparate mechanical responses from strong and stiff to soft and extensible. Pushing forward, the insight presented within this study will inform the development of next generation 3D printing materials, such as multicomponent hydrogels and composites.

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Liquid Chromatography High-Resolution TOF Analysis: Investigation of MSE for Broad-Spectrum Drug Screening

Clinical Chemistry ◽

10.1373/clinchem.2014.222976 ◽

2014 ◽

Vol 60 (8) ◽

pp. 1115-1125 ◽

Cited By ~ 37

Author(s):

Nandkishor S Chindarkar ◽

Michael R Wakefield ◽

Judith A Stone ◽

Robert L Fitzgerald

Keyword(s):

Liquid Chromatography ◽

High Resolution ◽

Drug Screening ◽

Broad Spectrum ◽

High Resolution Mass Spectrometry ◽

Screening Method ◽

High Energy ◽

Reference Laboratory ◽

Fragment Ions ◽

Tof Ms

Abstract BACKGROUND High-resolution mass spectrometry (HRMS) has the potential to supplement other drug screening platforms used in toxicology laboratories. HRMS offers high analytical specificity, which can be further enhanced by incorporating a fragment ion for each analyte. The ability to obtain precursor ions and fragment ions using elevated collision energies (MSE) can help improve the specificity of HRMS methods. METHODS We developed a broad-spectrum screening method on an ultraperformance liquid chromatography TOF mass spectrometer (UPLC-TOF-MS) using the MSE mode. A diverse set of patient samples were subjected to a simple dilute, hydrolyze, and shoot protocol and analyzed in a blind manner. Data were processed with 3 sets of criteria with increasing stringency, and the results were compared with the reference laboratory results. RESULTS A combination of retention time match (±0.2 min), a protonated analyte, and fragment ion mass accuracy of ±5 ppm produced zero false-positive results. Using these criteria, we confirmed 92% (253/275) of true positives. The positive confirmation rate increased to 98% (270/275) when the requirement for a fragment ion was dropped, but also produced 53 false positives. A total of 136 additional positive drug findings not identified by the reference methods were identified with the UPLC-TOF-MS. CONCLUSIONS MSE provides a unique way to incorporate fragment ion information without the need of precursor ion selection. A primary limitation of requiring a fragment ion for positive identification was that certain drug classes required high-energy collisions, which formed many fragment ions of low abundance that were not readily detected.

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All-inorganic Perovskite Nanocrystals: New Generation Scintillators for High-Resolution X-Ray Imaging

Nanoscale Advances ◽

10.1039/d1na00815c ◽

2022 ◽

Author(s):

Lu Lu ◽

Mingzi Sun ◽

Tong Wu ◽

Qiuyang Lu ◽

Baian Chen ◽

...

Keyword(s):

High Resolution ◽

Visible Light ◽

High Energy ◽

X Rays ◽

Inorganic Perovskite ◽

Perovskite Nanocrystals ◽

X Ray ◽

X Ray Imaging ◽

New Generation

With super strong penetrability, high-energy X-rays can be applied to probe the inner structure of target objects under nondestructive situations. Scintillation materials can down-convert X-rays into visible light, enabling the...

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Rapid High-Resolution Visible Light 3D Printing

ACS Central Science ◽

10.1021/acscentsci.0c00929 ◽

2020 ◽

Vol 6 (9) ◽

pp. 1555-1563 ◽

Cited By ~ 5

Author(s):

Dowon Ahn ◽

Lynn M. Stevens ◽

Kevin Zhou ◽

Zachariah A. Page

Keyword(s):

High Resolution ◽

3D Printing ◽

Visible Light

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High-resolution EM study of submicrometer-grained Al-Mg solid solution alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138993 ◽

1995 ◽

Vol 53 ◽

pp. 524-525

Author(s):

Z. Horita ◽

D. J. Smith ◽

M. Furukawa ◽

M. Nemoto ◽

R. Z. Valiev ◽

...

Keyword(s):

Electron Microscopy ◽

Solid Solution ◽

High Resolution ◽

Grain Boundaries ◽

Energy State ◽

High Energy ◽

Grain Structure ◽

Boundary Structure ◽

Solid Solution Alloy ◽

Average Grain Size

It is possible to produce metallic materials with submicrometer-grained (SMG) structures by imposing an intense plastic strain under quasi-hydrostatic pressure. Studies using conventional transmission electron microscopy (CTEM) showed that many grain boundaries in the SMG structures appeared diffuse in nature with poorly defined transition zones between individual grains. The implication of the CTEM observations is that the grain boundaries of the SMG structures are in a high energy state, having non-equilibrium character. It is anticipated that high-resolution electron microscopy (HREM) will serve to reveal a precise nature of the grain boundary structure in SMG materials. A recent study on nanocrystalline Ni and Ni3Al showed lattice distortion and dilatations in the vicinity of the grain boundaries. In this study, HREM observations are undertaken to examine the atomic structure of grain boundaries in an SMG Al-based Al-Mg alloy.An Al-3%Mg solid solution alloy was subjected to torsion straining to produce an equiaxed grain structure with an average grain size of ~0.09 μm.

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Ultra high resolution SEM at high voltage images individual fab fragments applied as molecular label to cell surface receptors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015232x ◽

1989 ◽

Vol 47 ◽

pp. 70-71

Author(s):

Klaus-Ruediger Peters

Keyword(s):

High Resolution ◽

High Energy ◽

Metal Coating ◽

Beam Diameter ◽

Surface Receptors ◽

Surface Mobility ◽

Metal Atoms ◽

Shadowing Effect ◽

Imaging Mode ◽

Deposition Techniques

Topographic ultra high resolution can now routinely be established on bulk samples in cold field emission scanning electron microscopy with a second generation of microscopes (FSEM) designed to provide 0.5 nm probe diameters. If such small probes are used for high magnification imaging, topographic contrast is so high that remarkably fine details can be imaged on 2DMSO/osmium-impregnated specimens at ribosome surfaces even without a metal coating. On TCH/osmium-impregnated specimens topographic resolution can be increased further if the SE-I imaging mode is applied. This requires that beam diameter and metal coating thickness be made smaller than the SE range of ~1 nm and background signal contributions be reduced. Subnanometer small probes can be obtained (only) at high accelerating voltages. Subnanometer thin continuous metal films can be produced under the following conditions: self-shadowing effect between metal atoms must be reduced through appropriate deposition techniques and surface mobility of metal atoms must be diminished through high energy sputtering and/or specimen cooling.

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High-resolution 3D printing in seconds

Nature ◽

10.1038/d41586-020-03543-3 ◽

2020 ◽

Vol 588 (7839) ◽

pp. 594-595

Author(s):

Cameron Darkes-Burkey ◽

Robert F. Shepherd

Keyword(s):

High Resolution ◽

3D Printing

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Rapid Crystallization and Kinetic Freezing of Site-Disorder in the Lithium Superionic Argyrodite Li6PS5Br

10.26434/chemrxiv.9794588 ◽

2019 ◽

Author(s):

Ajay Gautam ◽

Marcel Sadowski ◽

Nils Prinz ◽

Henrik Eickhoff ◽

Nicolo Minafra ◽

...

Keyword(s):

Elevated Temperatures ◽

Synthesis Method ◽

Reaction Times ◽

Ionic Conductivities ◽

Ionic Transport ◽

High Energy ◽

Superionic Conductors ◽

Rapid Crystallization ◽

Site Disorder ◽

Fast Cooling

Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li6PS5X (X = Cl, Br, I), a site-disorder between the anionsS2–and X–has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such disorder in Li6PS5Br can be engineered viathe synthesis method. By comparing fast cooling (i.e. quenching) to more slowly cooled samples, we find that anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with ab-initiomolecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within one minute of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that long reaction times with high energy consumption are not needed in this class of materials. The fact that site-disorder induced viaquenching is beneficial for ionic transport provides an additional approach for the optimization and design of lithium superionic conductors.

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