Synthesis of Compact Single-Chain Nanoparticles in Concentrated Solutions

Although a large family of covalently cross-linked robust single-chain nanoparticles (SCNPs) have been extensively synthesized, they are sparsely cross-linked, lacking precision control of the compactness. Herein, we propose a facile method to achieve robust SCNPs with tunable compactness by covalent cross-linking of the parent dynamic SCNPs. As proof of the concept, the dynamic SCNPs are large-scale synthesized at 200 mg/mL by the electrostatics-mediated intramolecular physical cross-linking of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA)-based polymers via amino/acid-specific interactions. The compactness of the dynamic SCNPs is greatly tunable from sparsely cross-linked to the globular state with scaling parameters from 0.57 to 0.34 by altering the cross-linking degree and spacer length of the cross-linker. The robust SCNPs with tunable compactness are derived by subsequent covalent cross-linking of the dynamic SCNPs. The SCNPs are featured with functional microdomains distinctly compartmentalized by using functional agents and preferential growth of functional materials thereby.