▎ 摘　　要

NOVELTY - Preparation of substrate composite fiber involves adding flaky graphite, sodium nitrate and concentrated sulfuric acid, mixing to obtain black viscous mixture, mixing with potassium permanganate, reacting, adding deionized water, heating, cooling, adding deionized water and hydrogen peroxide to obtain golden yellow graphene oxide solution, washing with deionized water and hydrochloric acid, centrifuging, dialyzing to obtain high-purity graphene oxide, adding tetrachloroauric acid aqueous solution to boiling water, stirring, adding trisodium citrate solution, reacting, cooling, adding cetyltrimethylammonium bromide aqueous solution to obtain gold seed solution, centrifuging to obtain gold nanoparticles solution, mixing with graphene oxide to obtain graphene oxide solution, centrifuging, concentrating to obtain wet spinning solution, wet-spinning spinning solution into composite fibers, washing, drying and reducing in hydroiodic acid/glacial acetic acid solution. USE - Preparation of substrate composite fiber for biosensor, food safety testing, medical testing and wearable electronic fabrics. ADVANTAGE - The prepared substrate composite fiber overcomes the defects like poor stability, signal confusion, poor flexibility, and poor biocompatibility compared to existing substrate composite fiber. DETAILED DESCRIPTION - Preparation of substrate composite fiber involves performing modified Hummers method to prepare graphene oxide by adding flaky graphite, sodium nitrate and concentrated sulfuric acid in mass ratio of 0.1-1:0.1-:10-60, mixing at 0-8 degrees C for 20-60 minutes to obtain black viscous mixture, mixing black viscous mixture and potassium permanganate in mass ratio of 0.1-1:1-10, reacting for 30-90 degrees C, raising temperature to 30-40 degrees C and stirring for 30-90 minutes, adding 50-150 mL deionized water, heating to 80-100 degrees C for 10-60 minutes, cooling to room temperature, adding 100-300 mL deionized water and 1-10 mL of 20-50% hydrogen peroxide solution for 2-7 times to obtain golden yellow graphene oxide solution, washing with deionized water and 5-20% hydrochloric acid multiple times, centrifuging washed product, dialyzing for 3-10 day to obtain high-purity graphene oxide, preparing gold nanoparticles by adding 0.1-1 ml of 5-50 mM tetrachloroauric acid aqueous solution to 10-100 ml boiling water, stirring at 200-1000 rpm for 5-20 minutes, adding 50-200 mu l of 0.1-1 M trisodium citrate solution, stirring at 500-1500 rpm until solution changes from light yellow to dark red, reacting at 500-1500 rpm for 20-60 minutes, cooling to room temperature, adding 10-100 ml of 0.01-0.1 M cetyltrimethylammonium bromide aqueous solution to obtain gold seed solution, centrifuging at 1000-3000 rpm to remove free cetyltrimethylammonium bromide to obtain gold nanoparticles solution, mixing gold nanoparticles solution and graphene oxide in a mass ratio of 0.01-0.5:1-100 to obtain graphene oxide solution, stirring for 12-24 hours to obtain graphene oxide loaded with gold nanoparticles, centrifuging at 8000-12000 rpm, concentrating to obtain wet spinning solution, using aqueous solution of calcium chloride in ethanol as coagulation bath, wet-spinning the spinning solution using micro-injection pump to obtain graphene oxide-gold nanoparticles composite fibers, washing graphene oxide-gold nanoparticles composite fibers and drying over aqueous ethanol solution, and reducing in hydroiodic acid and glacial acetic acid solution in ratio of 2-4:5-10 at 30-35 degrees C to obtain graphene oxide-gold nanoparticles surface-enhanced Raman spectroscopy substrate composite fibers.