Molecular ordering of precursor films during spreading of tiny liquid droplets

In this work we address a feature of spreading dynamics of tiny liquid droplets on solid surfaces, namely, the case where the ends of the molecules have different interactions with the surface. We consider a simple model of dimers and short chainlike molecules which cannot form chemical bonds with the surface. We study the spreading dynamics by molecular dynamics techniques. In particular, we examine the microscopic structure of the time-dependent precursor film and find that in some cases it can exhibit a high degree of local order. This order persists even for flexible chains. Our results suggest the possibility of extracting information about molecular interactions from the structure of the precursor film.