Issue 31, 2022

Growth mechanism and microstructures of Cu2O/PVP spherulites


Cu2O spherulites are solvothermaly fabricated by using Cu(NO3)2 as the starting material and polyvinylpyrrolidone (PVP) as a multifunctional growth agent. The specimens at different growth stages are investigated by using X-ray diffraction, electron microscopy, energy dispersive X-ray spectroscopy, soft X-ray emission spectroscopy and infrared spectroscopy. The formation mechanism of Cu2O spherulites is proposed accordingly. Hierarchically, the spherulites are composed of needle-like submicron-rods lying along the radial orientations. The submicron-rods are constructed by piling up of small Cu2O/PVP spheres. The embedded Cu2O nanocrystallites can generate a dipolar field in each along the [100] direction. They deposit at the surface of a negatively charged PVP-containing spherical core, and self-oriented along the radial directions. Therefore, all the Cu2O nanocrystallites would have their positively charged (100) facet facing to the core and their negatively charged ([1 with combining macron]00) facet turning towards to the spherulite surface, leading to a negatively charged surface of spherulites. Unlike randomly oriented nanocrystallites embedded in polymer microspheres, the spherulites would not undergo surface recrystallisation into a single crystal shell due to the restricted potential of local shift and rotation of the nanocrystallites by the Coulomb force from the core. This work provides new perspective towards the formation of spherulites and their structural properties.

Graphical abstract: Growth mechanism and microstructures of Cu2O/PVP spherulites

Supplementary files

Article information

Article type
26 May 2022
27 Jun 2022
First published
11 Jul 2022
This article is Open Access
Creative Commons BY license

RSC Adv., 2022,12, 20022-20028

Growth mechanism and microstructures of Cu2O/PVP spherulites

W. Sun and W. Zhou, RSC Adv., 2022, 12, 20022 DOI: 10.1039/D2RA03302J

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