Nanoscale measurement of adhesion forces and atomic-scale mechanisms at CSH/SiO2 and CSH/PVP-co-PAA interfaces

Interface between calcium silicate hydrate (CSH) and polymers is crucial for the mechanical properties and durability. However, direct experimental determination of interfacial mechanics at nanoscale has not been reported. Herein, atomic force microscopy (AFM) with grafted Poly (1-vinylpyrrolidone- co -acrylic acid) (PVP-co-PAA) on AFM tips were utilized to measure interfacial properties between CSH and PVP-co-PAA under four C/S at nanoscale. The interfacial force curves were clearly presented for the first time. Results showed that compared to as-received tip, representing SiO 2 , the adhesive force and energy dissipation increased by 72.42 % and 417 %. Interface separation speed was delayed by 300 % ∼ 400 %. Molecular simulations of interfacial separation aligned with AFM experimental results, where interfacial ion-pair, dynamics stability and polymer conformational changes provided insights for AFM experiment on adhesion force and delay of interface separation speed. Determination of interfacial mechanics by AFM experiment and insights by molecular simulation decoded CSH/PVP-co-PAA interfaces thoroughly.