Leveraging Polymer Dots for Cementitious Material Optimization: Enhancing Mechanical Properties

Introduction: This study investigates Polymer Dots (PDs) as low-cost, dispersible nanomaterials to enhance cementitious materials, thereby overcoming the limitations of traditional nanomaterials, including high cost and poor dispersion. Methods: PDs are synthesized via an ambient-temperature Schiff base reaction between ophenylenediamine and p-benzoquinone. The dispersion stability of PDs in simulated concrete pore solutions is evaluated using UV-vis and photoluminescence spectroscopy. Mechanical properties are assessed through compressive and flexural strength tests. Hydration kinetics are analyzed via isothermal calorimetry, while phase composition and microstructure are characterized using XRD, TGA/DTG, SEM, and MIP. Results: The incorporation of 0.2 wt.% PDs significantly improve the 28-day compressive and flexural strengths by 21.2% and 19.3%, respectively. PDs accelerate cement hydration, increasing the exothermic peak intensity by 31.8% and advancing its occurrence by 3.7 h. PDs enhance the formation of C-S-H gel, reduce total porosity, and refine pore structure with a higher proportion of harmless pores. Discussion: PDs act as effective nucleation sites, promoting hydration and densifying the microstructure through increased C-S-H formation and pore refinement. Their superior dispersion stability in alkaline environments overcomes a major limitation of traditional nanomaterials. However, the study is limited to Portland cement and PDs dosages ≤0.2 wt.%; further validation under broader mix designs and scaled synthesis is needed. Conclusion: PDs exhibit exceptional potential as a low-cost, highly dispersible nanoadditive for enhancing the mechanical performance of cementitious materials. This work lays the foundation for developing sustainable, high-performance concrete infrastructure through the innovative use of nanomaterials.