Bimodal nanolatexes prepared via polymerization-induced self-assembly: losing control in a controlled manner

The combination of reversible addition-fragmentation chain-transfer (RAFT) polymerization with polymerization-induced self-assembly (PISA) is known to yield monodisperse nanolatexes. Interestingly, based on the results of the current study, reproducible bimodal nanolatexes were shown to be the result of chain extension of protonated poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) with methyl methacrylate (MMA) in water when aiming for a longer hydrophobic block, for which we provide the first imaging data to our knowledge. The bimodality was found to be induced by the hydrophilic Z-group of the RAFT agent, which has been reported in the literature to be the cause of bimodal molecular weight distributions in RAFT-mediated PISA in emulsion polymerization. Moreover, the advantages of such reproducible bimodal size distribution nanolatexes in coating applications were investigated briefly, underlining the possibilities of their one-pot synthesis. It was found that when bimodal nanolatexes are adsorbed onto cellulose filter paper, the contact angle against water is higher compared to chemically similar monomodal nanolatexes. Also, the morphological arrangement was found to be dependent on the drying protocol. This study aims to expand our understanding on bimodality and the identification of parameters that could promote it on demand to target high-end applications.

Automated summary

The combination of RAFT polymerization and PISA can produce monodisperse nanolatexes. This study demonstrates the synthesis of reproducible bimodal nanolatexes by extending protonated PDMAEMA with MMA in water and provides the first imaging data. The bimodality is induced by the hydrophilic Z-group of the RAFT agent, which has been reported to cause bimodal molecular weight distributions in RAFT-mediated PISA. The advantages of such nanolatexes in coating applications are briefly explored, including their one-pot synthesis, higher contact angle against water when adsorbed on cellulose filter paper, and morphological arrangement dependent on the drying protocol.