▎ 摘　　要

NOVELTY - Preparation of film involves: (i) uniformly dripping Tris solution containing dopamine hydrochloride on surface of hydrophobic polyvinylidene fluoride (PVDF) film, allowing to stand for 6-12 hours, washing excess polydopamine by using a lot of deionized water, placing in oven, and drying at 60-80℃ for 2-3 hours to obtain PVDF film substrate; (ii) dispersing thiourea into aqueous solution containing graphene oxide, and heating to make it cross-linked to obtain graphene oxide-thiourea solution; and (iii) placing PVDF film substrate in vacuum suction filter bottle, wetting by using ethanol, adding graphene oxide-thiourea solution, suction-filtering, taking-off film and placing it in oven, and drying. USE - Preparation method of film useful for photothermal film distillation device (claimed) for desalting treatment of salt-containing solution or wastewater purification. ADVANTAGE - The film has excellent and stable photothermal performance and anti-wetting ability, and effectively retain macromolecule i.e. surfactant, and volatile small molecular substance, which can enter condensed water side by hydrophobicity, so as to realize recycling of volatile substance through condensed liquid. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: film, prepared by above method; and photothermal film distillation device.