  Silicone is frequently used as a model system to investigate and tune wetting
on soft materials. Silicone is biocompatible and shows excellent thermal,
chemical, and UV stability. Moreover, the mechanical properties of the surface
can be easily varied by several orders of magnitude in a controlled manner.
Polydimethylsiloxane (PDMS) is a popular choice for coating applications such
as lubrication, self-cleaning, and drag reduction, facilitated by low surface
energy. Aiming to understand the underlying interactions and forces, motivated
numerous and detailed investigations of the static and dynamic wetting behavior
of drops on PDMS-based surfaces. Here, we recognize the three most prevalent
PDMS surface variants, namely liquid-infused (SLIPS/LIS), elastomeric, and
liquid-like (SOCAL) surfaces. To understand, optimize, and tune the wetting
properties of these PDMS surfaces, we review and compare their similarities and
differences by discussing (i) the chemical and molecular structure, and (ii)
the static and dynamic wetting behavior. We also provide (iii) an overview of
methods and techniques to characterize PDMS-based surfaces and their wetting
behavior. The static and dynamic wetting ridge is given particular attention,
as it dominates energy dissipation, adhesion, and friction of sliding drops and
influences the durability of the surfaces. We also discuss special features
such as cloaking and wetting-induced phase separation. Key challenges and
opportunities of these three surface variants are outlined.
