Wettability of polymer materials with different liquids and effect of contact angle test liquids on calculated surface free energy value

OpenAlex İngilizce

In the first stage of this study, the contact angles (θ) of PC (polycarbonate), PMMA [poly(methyl methacrylate)], and PTFE (polytetrafluoroethylene), which are widely used polymers for various purposes, with different polar [water (W), formamide (F), glycerol (GL), and ethylene glycol (EG)] and nonpolar [diiodomethane (DIO), bromonaphthalene (BRO), and also dodecane (DOD), decane (DEC), octane (OCT), heptane (HEP), and hexane (HEX) from the n-alkane homolog series] liquids were measured and the wettability behavior was investigated in detail. In the second stage, 8 different binary liquid groups were arranged from these liquids whose θs were measured, and the surface free energies (SFE) of the polymers were calculated according to the OWRK-Fowkes method and their standard deviations (SDs) were determined. According to the obtained results, the wetting behavior of nonpolar liquids on polymers differed from that of polar liquids. While the decrease in θ due to surface tension (i.e. the increase in wettability) followed a linear trend for polar liquids, there was a sudden decrease in the range of 50.8–25.4 mN/m for nonpolar liquids and there was no significant change afterward. According to the water θ data, the hydrophobic character of the polymers was ranked as follows from largest to smallest: PTFE (θ: 91.1°) > PC (θ: 81.5°) > PMMA (θ: 77.7°). The average SFE and SDs of the polymers calculated by the OWRK-Fowkes method were as follows: PC 43.8 ± 1.1, PMMA 41.1 ± 5.3, and PTFE 38.9 ± 1.4 mJ/m2. Accordingly, it was determined that the effect of the selected liquid groups on the OWRK-Fowkes SFE values of the polymers was between 2.5% and 12.9%.