Hasti Shekaryar - Undergraduate student, Kharazmi University
Tahere Ebrahimi Sadrabadi - Assistant professor, Department of Advanced Materials and Renewable Energy, Iranian Research Organization in Science and Technology (IROST)
Davood Sadeghi Fateh - Assistant professor, Department of Chemical Technology, Iranian Research Organization in Science and Technology (IROST)
Marjan Rajabi - Assistant professor, Department of Advanced Materials and Renewable Energy, Iranian Research Organization in Science and Technology (IROST)

This study reports the effects of solvent on the surface properties of rubbed polyvinyl alcohol (PVA)thin films deposited on the glass substrate by the spin-coating method. The used solvents were waterand methanol diluted ۲۰% w/w aqueous solution. Thin films are characterized by atomic forcemicroscopy, Fourier transform infrared (FTIR) spectroscopy, and contact angle measurements. FTIRspectra showed the characteristic valleys, which indicated the presence of C-H and O-H bonds in thechemical structure of PVA. PVA thin film thicknesses measured by AFM are in the range of ۱۰۰-۲۰۰nm. The contact angles of PVA thin layers are also characterized using the sessile drop method. Usingwater and methanol as solvents of PVA for coating materials has a great impact on PVA molecules'chemical structure. Furthermore, mechanical rubbing of the surface of the PVA thin film by velvetcauses a rearrangement of functional groups at the PVA chains. Due to the variation of chemicalstructure and reorientation of PVA chains, the polarity of the surface alters which correlates to thesurface contact angle.

Polyvinyl alcohol, thin film, Spin-coating, Rubbing, Alignment layer, Surface characterization