Force Regulation by Sequence-Defined Polyelectrolytes

In order to achieve multifunctional adhesive materialswith waterand salt tolerance, it is crucial to understand the electrostaticmechanism of nanoconfined polyelectrolytes (PEs) with specific monomersequences. Here, using density functional theory (DFT), self-consistentfield theory (SCFT), and molecular dynamics (MD) simulation, we analyzedthe microstructures of sequence-defined PEs confined in a nanoscaleslit and the relationship between sequences and the attractive forcesinduced by the nanoconfined PEs. Among three sequence-defined (alternating[A], tapered [T], and reversely tapered [R] sequence) PEs, due tothe formation of stable multibridge conformations, [A]-sequence PEsinduce the strongest attractive forces even in the case with highsalt concentrations, i.e., the best salt tolerance. It is worth emphasizingthat salt enhancement of attractive forces occurs in systems with[A]-sequence PEs due to the screening of repulsive interactions betweenPE chains. In contrast, in systems with [T]-sequence PEs, the shieldingof the attractive interactions between surfaces and charged monomerssignificantly attenuates the attractive forces between surfaces athigh salt concentrations. In addition, the strength of attractiveforces can be regulated by block number N (b). At high charge fractions such as f (c) = 0.5, the attractive forces induced by [A]-sequence PEs becomestronger with N (b), while at low chargefractions such as f (c) = 0.2, the attractiveforces vary nonmonotonically with N (b) dueto the electrostatic correlations.