Maintaining Alignment at High Mineral Loading in Wire-Frame Electrospinning of Hydroxyapatite/Pan Nanofibers Publisher

Summary: How can we optimize nanofiber alignment? A study found that interwire spacing (IWS) is crucial for directing nanofiber orientation, even at high inorganic loadings. This could revolutionize composite materials! #Nanotechnology #MaterialsScience

Nouri A ; Shahabi S ; Valijam S ; Mcvey M ; Gholamhoseini A ; Nasiri N
Source: ACS Applied Polymer Materials Published:2026

Abstract

The scalable fabrication of highly aligned composite nanofibers remains challenging, particularly at high inorganic loadings where jet instability and loss of orientation commonly occur. Here, we engineer a modular wire-frame collector that generates a spatially confined anisotropic electric-field corridor to direct fiber alignment during electrospinning. Using polyacrylonitrile (PAN) reinforced with hydroxyapatite (HA) nanoparticles (10–80 wt %), we demonstrate that precise control of interwire spacing (IWS) governs the field gradient and, consequently, nanofiber orientation. Quantitative directionality analysis identifies 1.0 cm IWS as optimal under the specific drum geometry and operating conditions used in this study. Notably, alignment is preserved even at 80 wt % HA, contrasting with prior composite systems where increased solids content disrupts orientation. XRD, FTIR, and DSC/TGA analyses confirm that PAN semicrystallinity and HA phase integrity are retained, with thermal stability enhanced through heat-sink and mobility-restriction effects rather than altered reaction pathways. Mechanical testing shows a composition-dependent balance between modulus enhancement and tensile failure strain. Finite element simulations corroborate the experimentally observed field confinement. Collectively, this work establishes IWS as a key geometric parameter for electric-field-guided alignment and provides a generalizable strategy for producing highly oriented polymer–ceramic nanofibers at high mineral loadings. © 2026 American Chemical Society