▎ 摘　　要

NOVELTY - Preparing photothermal gel involves dispersing zwitterionic polymer monomer, cationic polymer monomer, crosslinking agent and photothermal nanoparticle in water to obtain precursor solution, adding initiator to precursor solution, heating to obtain free radical polymerization reaction, and adding catalyst to the precursor solution to initiate a radical polymerization reaction to obtain the photothermal hydrogel. USE - Method for preparing photothermal gel for use in seawater desalination or sewage treatment, and photothermal conversion evaporator (all claimed). ADVANTAGE - The prepared photothermal gel has anti-adhesion, bacteriostasis and salt resistance while achieving good photothermal water evaporation efficiency, and ensues that the material can continuously and stably conduct photothermal hot water evaporation to generate fresh water. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. a photothermal water gel prepared by preparation method; and 2. a photothermal conversion evaporator, which comprises: a photothermal hydrogel.