{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T13:22:30Z","timestamp":1787923350015,"version":"build-2784847793"},"reference-count":29,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T00:00:00Z","timestamp":1787875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52304043"],"award-info":[{"award-number":["52304043"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["52304043"],"award-info":[{"award-number":["52304043"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Conventional partially hydrolyzed polyacrylamide (HPAM) suffers severe chain coiling, viscosity attenuation and precipitation under high-temperature and high-salinity reservoir brines, restricting its tertiary oil recovery efficiency. Herein, a novel carbon quantum dot hybrid terpolymer (QDHSTP) was synthesized via free-radical copolymerization, where silane-modified nitrogen-doped carbon quantum dots (FNCQDs) were covalently bonded to acrylamide (AM)\/2-acrylamido-2-methylpropane sulfonic acid (AMPS)\/diallyldimethylammonium chloride (DMDAAC) backbones. FTIR, 1H NMR and thermogravimetric analysis (TGA) verified successful grafting of FNCQDs, while SEM revealed a continuous three-dimensional entangled network constructed by polymer chains. Steady and oscillatory rheology systematically characterized the solution viscoelasticity: QDHSTP solutions followed the power-law shear-thinning model, with flow behavior index n decreasing from 0.698 to 0.676 and consistency factor k rising from 80.91 to 131.13 mPa\u00b7sn as concentration increased from 2000 to 3000 mg\/L. All samples behaved as viscosity-dominated viscoelastic fluids, with elastic modulus exhibiting stronger frequency dependence. Benefiting from embedded FNCQDs, QDHSTP retained 79.74% and 76.06% of initial viscosity in 1.0 \u00d7 104 mg\/L NaCl and CaCl2 brine, respectively, markedly better than that of the polymer without incorporated FNCQDs respectively, and maintained thickening capacity at 90 \u00b0C. Artificial sandstone core flooding demonstrated an incremental oil recovery of 29.8% over baseline waterflooding, attributed to mobility control and elastic residual oil stripping. This covalent nanohybrid strategy provides a facile route to construct thermo-salt tolerant polyacrylamides, offering a promising candidate polymer for harsh oil reservoir chemical flooding.<\/jats:p>","DOI":"10.3390\/polym18172084","type":"journal-article","created":{"date-parts":[[2026,8,28]],"date-time":"2026-08-28T12:27:46Z","timestamp":1787920066000},"page":"2084","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Quantum Dot-Hybridized Temperature- and Salt-Resistant Polyacrylamide for Enhanced Oil Recovery in High-Temperature and High-Salinity Reservoirs"],"prefix":"10.3390","volume":"18","author":[{"given":"Hua","family":"Li","sequence":"first","affiliation":[{"name":"Xi\u2019an Changqing Chemical Group Co., Ltd., Xi\u2019an 710200, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"given":"Jingjing","family":"He","sequence":"additional","affiliation":[{"name":"Xi\u2019an Changqing Chemical Group Co., Ltd., Xi\u2019an 710200, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Rui","family":"Jing","sequence":"additional","affiliation":[{"name":"Xi\u2019an Changqing Chemical Group Co., Ltd., Xi\u2019an 710200, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]},{"given":"Song","family":"Wang","sequence":"additional","affiliation":[{"name":"Engineering Technology Department, PetroChina Xinjiang Oilfield Company, Karamay 834000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"}]},{"given":"Aihui","family":"Li","sequence":"additional","affiliation":[{"name":"Xi\u2019an Changqing Chemical Group Co., Ltd., Xi\u2019an 710200, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Ting","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Daijun","family":"Du","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"}]},{"given":"Suhan","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Petroleum and Natural Gas Engineering, Chongqing University of Science and Technology, Chongqing 401331, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8154","DOI":"10.1021\/acs.energyfuels.8b01411","article-title":"Solution properties and displacement characteristics of core-shell hyperbranched associative polyacrylamide for enhanced oil recovery","volume":"32","author":"Du","year":"2018","journal-title":"Energy Fuels"},{"key":"ref_2","first-page":"1779","article-title":"Improving heavy oil recovery in the polymer flooding process by utilizing hydrophilic silica nanoparticles","volume":"1","author":"Khalilinezhad","year":"2017","journal-title":"Energy Sources Part A Recovery Util. 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