Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is a promising material because of its favorable electrical and mechanical properties, stability in ambient environments, and biocompatibility. It finds broad application in energy storage, flexible electronics, and bioelectronics. Additive manufacturing opens a plethora of new avenues to form and shape PEDOT:PSS, allowing for the rapid construction of customized geometries. However, there are difficulties in printing PEDOT:PSS while maintaining its attractive properties. A 3D printing method for PEDOT:PSS using a room‐temperature coagulation bath‐based direct ink writing technique is reported. This technique enables fabrication of PEDOT:PSS into parts that are of high resolution and high conductivity, while maintaining stable electrochemical properties. The coagulation bath can be further modified to improve the mechanical properties of the resultant printed part via a one‐step reaction. Furthermore, it is demonstrated that a simple post‐processing step allows the printed electrodes to strongly adhere to several substrates under aqueous conditions, broadening their use in bioelectronics. Employing 3D printing of PEDOT:PSS, a cortex‐wide neural interface is fabricated, and intracranial electrical stimulation and simultaneous optical monitoring of mice brain activity with wide field calcium imaging are demonstrated. This reported 3D‐printing technique eliminates the need for cumbersome experimental setups while offering desired material properties.
Suitability of 3D-Printed devices for low-temperature geochemical T experiments
Desktop 3D printing stereolithography (SLA) is a fabrication technique based on photopolymerization that can be used to efficiently create novel reaction devices for laboratory geochemistry with complex features (e.g. internal channels, small volumes) that are beyond the capabilities of traditional machining methods. However, the stability of 3D printed parts for low-temperature aqueous geochemical conditions has not been carefully evaluated. Furthermore, it is unclear what criteria should be used when attempting to optimize the mechanical and chemical properties during post-processing steps. Addressing these challenges is important for determining the suitability of 3D printed devices for laboratory investigations such as mineral precipitation/dissolution ex- periments. Here, we use thermogravimetric analysis (TGA) profiles, dynamic mechanical analysis (DMA), and chemical extraction of leachables to show how ultraviolet (UV) post-curing can optimize properties of a com- mercial photo-reactive resin (Formlabs Standard Clear). The mechanical and chemical stability of the post-cured material was enhanced and a working temperature of up to 80 °C was determined. We further provide data showing the stability and compatibility of the material in aqueous conditions of pH 0, 5.7 and 12. As SLA 3D printing is still an emerging and rapidly developing technology, the method presented here will provide a fra- mework for assessing how new printer types and materials (i.e. resins) impact the suitability of SLA printed devices for future experimental studies.
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- Award ID(s):
- 1652237
- NSF-PAR ID:
- 10100484
- Date Published:
- Journal Name:
- Applied geochemistry
- Volume:
- 98
- ISSN:
- 1872-9134
- Page Range / eLocation ID:
- 121 - 126
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract -
null (Ed.)3D printing is an essential tool for rapid prototyping in a variety of sectors such as automotive and public health. The 3D printing market is booming, and it is projected that it will continue to thrive in the coming years. Unfortunately, this rapid growth has led to an alarming increase in the amount of 3D printed plastic waste. 3D printing processes such as stereolithography (SLA) and digital light projection (DLP) in particular generally produce petroleum-based thermosets that are further worsening the plastic pollution problem. To mitigate this 3D printed plastic waste, sustainable alternatives to current 3D printing materials must be developed. The present review provides a comprehensive overview of the sustainable advances in SLA/DLP 3D printing to date and offers a perspective on future directions to improve sustainability in this field. The entire life cycle of 3D printed parts has been assessed by considering the feedstock selection and the end-of-use of the material. The feedstock selection section details how renewable feedstocks (from lignocellulosic biomass, oils, and animal products) or waste feedstocks ( e.g. , waste cooking oil) have been used to develop SLA/DLP resins. The end-of-use section describes how materials can be reprocessed ( e.g. thermoplastic materials or covalent adaptable networks) or degraded (through enzymatic or acid/base hydrolysis of sensitive linkages) after end-of-use. In addition, studies that have employed green chemistry principles in their resin synthesis and/or have shown their sustainable 3D printed parts to have mechanical properties comparable to commercial materials have been highlighted. This review also investigates how aspects of sustainability such as recycling for feedstock/end-of-use or biodegradation of 3D printed parts in natural environments can be incorporated as future research directions in SLA/DLP.more » « less
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Due to its excellent chemical/thermal stability and mechanical robustness, hexagonal boron nitride (hBN) is a promising solid matrix material for ionogels. While bulk hBN ionogels have been employed in macroscopic applications such as lithium-ion batteries, hBN ionogel inks that are compatible with high-resolution printing have not yet been realized. Here, we describe aerosol jet-printable ionogels using exfoliated hBN nanoplatelets as the solid matrix. The hBN nanoplatelets are produced from bulk hBN powders by liquid-phase exfoliation, allowing printable hBN ionogel inks to be formulated following the addition of an imidazolium ionic liquid and ethyl lactate. The resulting inks are reliably printed with variable patterns and controllable thicknesses by aerosol jet printing, resulting in hBN ionogels that possess high room-temperature ionic conductivities and storage moduli of >3 mS cm −1 and >1 MPa, respectively. By integrating the hBN ionogel with printed semiconductors and electrical contacts, fully-printed thin-film transistors with operating voltages below 1 V are demonstrated on polyimide films. These devices exhibit desirable electrical performance and robust mechanical tolerance against repeated bending cycles, thus confirming the suitability of hBN ionogels for printed and flexible electronics.more » « less
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/doi.org/10.1016/j.apgeochem.2018.08.012
