Ferrofluids prepared by dispersing superparamagnetic Fe₃O₄@C core–shell nanoparticles in water exhibited exceptional enhancement in thermal conductivity without an external magnetic field.

In this article, ZnO thin-film deposition on a glass substrate was done using microwave induced oxygen plasma based CVD system. The prepared thin-films were tested in terms of crystallinity and optical properties by varying the microwave power. The effect of power variation on the morphology and size of final products was carefully investigated. The crystal structure, chemical composition and morphology of the final products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, Raman spectroscopy and photoluminescence (PL). This technique confirmed the presence of hexagonal ZnO nanocrystals in all the thin-films. The minimum crystallite grain size as obtained from the XRD measurements was ~9.7 nm and the average diameter was ~18 nm.

In this paper, the electrospinning technique was used to obtain multi-walled carbon nanotubes (MWCNTs) supported on electrospun polyvinylidene fluoride (PVDF) nanofibres (NFs) (PVDF/MWCNTs), a composite-based mat of NFs. The surface morphology of the PVDF/MWCNTs NFs was analysed by a field effect scanning electron microscope. The thickness of the NFs mat varies with the time and concentration of MWCNTs. The contact angle (CA) measurement shows that 2.5 wt% of MWCNTs in NF mat shows 61° CA which suggests the hydrophilic nature of the prepared NF mat. Fourier transform infrared and Raman spectroscopy revealed the implantation of MWCNTs in PVDF matrix and side wall attachment with polymer chain. X-ray diffraction and FTIR studies show that as the MWCNT content increases, the α-phase in PVDF decreases, indicating that MWCNT has a strong effect on phase transformation. Consequently, the NFs show an almost linear capacitive response. They showed that the high-capacitive changes in PVDF/MWCNTs’ NFs are achieved at 2.5 wt% MWCNTs’ addition at different humidity levels. The sensitivity of the PVDF/MWCNTs’ (2.5 wt%) NF mat-based capacitive sensor exhibits high sensitivity ∼0.71pF/%RH. Hence, PVDF/MWCNTs’ NFs perform attention-grabbing properties for the humidity sensing application.