PVA is an abbreviation for polyvinyl alcohol, a water-soluble material. It is often used with multi-extruder FDM 3D printers as a support material. The biggest advantage of PVA filament is its ability to dissolve in water. This means there are no ugly marks left on the print after the support material is removed.
PVA in general works very well with PLA and Nylon filaments since it requires same operating conditions such as the desired temperature.
Parts printed with PVA supports usually need to be placed in water for a few hours (depending on the manufacturer’s specifications), until there‘s no undissolved material left.
Remember, PVA is a hydrophilic material, “it likes water” so the material connects with water molecules which results in PVA dissolving in water. PLA is a hydrophobic material so it “doesn’t like water” which means PVA and PLA are a perfect match because putting a PLA part in water does not affect it since it’s made out of a hydrophobic material, it doesn’t absorb water.