▎ 摘　　要

NOVELTY - Preparing graphene-polydopamine-silver core-shell nanoparticle comprises (i) dispersing graphene in dimethylformamide to obtain graphene suspension; (ii) dissolving dopamine hydrochloride in tris-hydrochloride buffer solution, adjusting pH to 8-9, adding graphene suspension, magnetically stirring, heating, reacting, filtering, washing with deionized water for 2-3 times, and drying to obtain graphene-polydopamine nanoparticle; and (iii) dissolving polyvinylpyrrolidone in silver ammonia solution, adding graphene-polydopamine nanoparticle, magnetically stirring, heating, reacting, centrifuging, and washing. USE - The nanoparticle is useful for preparing polymer composite film for manufacturing sensor or brake (all claimed). ADVANTAGE - The nanoparticle improves dielectric properties of polymer and prevents agglomeration of conductive fillers, so the fillers form a uniform dispersion matrix in the polymer. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the polymer composite film, comprising blending graphene-polydopamine-silver core-shell type nanoparticle with elastomer solution, performing impurity filtration and vacuum extraction of the sol, paving film and drying.