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Abstract Melt electrowriting (MEW) is an emerging additive process for high‐fidelity, microscale fibrous scaffold fabrication. However, achieving precise multilayered MEW‐enabled scaffolds is limited by the entrapped residual charges owing to charge‐based mechanisms. Specifically, the semi‐conductive nature of processed materials causes retainment of net positive charges and jet–fiber repulsion, while exposure to the electric field yields charge polarization with resultant jet–fiber attraction. These competing effects work in tandem to determine the distinctive features of jet–fiber interaction. To deconstruct various charge‐related phenomena, the collector temperature is manipulated as a key process variable to investigate its effect on printing outcomes in two printing modes. Moreover, energy analysis is introduced to explain how collector temperature affects the polarization extent, along with the jet–fiber interaction and printing outcomes. In single fiber printing mode, sets of two parallel fibers with variable set interfiber distances (sSf) are printed at different collector temperatures. At a lowsSfthreshold, significant fiber attraction is observed, but no significant difference is observed among the cases at different collector temperatures. In scaffold printing mode, 200‐layer scaffolds are printed at different collector temperatures, and the wall morphologies are found to vary with location, layer number, and collector temperature.
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Quantitative Investigation into the Design and Process Parametric Effects on the Fiber‐Entrapped Residual Charge for a Polymer Melt Electrohydrodynamic Printing Process
Abstract The printing accuracy of the melt electrowriting (MEW) process is adversely affected by residual charge entrapped within the printed fibers. To mitigate this effect, the residual charge amount (Qr) must first be accurately determined. In this study,Qris measured by a commercial electrometer at a nanocoulomb scale for MEW‐enabled scaffolds. Based on this enabling measurement, the effects of various design parameters (including substrate surface conductivityσ, printing timet, layer numberN), and process parameters (including voltageU, translational stage speedv, and material temperatureTm), onQrare investigated. An increase ofσor decrease ofNhelps to decreaseQr. The effects of different process parameters on the residual charge can be either dependent or independent of fiber morphologies. Moreover, the fiber‐morphology dependent and independent effect can be either synergistic (UandTm) or antagonistic (e.g.,v) for different process parameters. Under same conditions,Qrin the interweaving scaffold design is generally smaller than that in the non‐interweaving scaffold design. These results help to furnish necessary insights into the charge dissipation process for a melt‐based electrohydrodynamic printing process while providing a systematic methodology to mitigate the residual charge accumulation.
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- Award ID(s):
- 1663095
- PAR ID:
- 10446147
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Macromolecular Materials and Engineering
- Volume:
- 307
- Issue:
- 3
- ISSN:
- 1438-7492
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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