SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: Wetting, Droplets and Microfluidics I (joint session DY/CPP)

CPP 34.9: Talk

Wednesday, March 29, 2023, 12:15–12:30, ZEU 148

effect of deposition method on the static contact angle of nanodroplets measured by AFM — •mohammadali hormozi and regine von klitzing — soft matter at interface, tu darmstadt, darmstadt, Germany

The wetting properties of substrates are often described by the static contact angle of a particular liquid. The contact angle depends on many parameters like substrate chemistry, liquid properties, and environment condition. In this study, we show that the method of depositing the liquid phase on the solid phase can play an important role for the static contact angle. For this purpose, microscale droplets of non-volatile liquids including Polyethylene Glycol (PEG200) and Squalane are deposited on the silanized substrate using four different methods. These methods are either based on nucleation (condensation and solvent exchange) or printing (inkjet and microcontact printing) of droplets. The contact angle of the microdroplets is scanned with an AFM and allows detailed analysis of the three phase contact line on a nm scale. The final static contact angle of the microdroplets is compared with the macroscopic contact angle determined by optical methods. Droplets formed via nucleation show smaller contact angle than printed ones. The latter ones were closer to the macroscopic contact angle. We will discuss this phenomenon.