Nanostructured Membranes from Soft and Hard Nanoparticles Prepared via RAFT‐mediated PISA

Abstract

Reversible addition‐fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) is used to prepare a series of near mono‐dispersed poly(2‐(dimethylamino)ethyl methacrylate)‐poly(benzyl methacrylate) (PDMA‐PBzMA) diblock copolymer nanoparticles in an ethanol–water binary mixture via polymerization‐induced self‐assembly. A relatively long PDMA (DP = 88) chain transfer agent is targeted to ensure that only spherical morphologies are obtained. High (>99%) BzMA monomer conversions can be achieved within 24 h when targeting degrees of polymerization (DP) of up to 1000. The resulting particles are analyzed using dynamic light scattering and transmission electron microscopy (TEM). Particles with PBzMA DPs of 500 and 1000 are used as templates for deposition of silica particles. TEM images confirm that tetramethyl orthosilicate precursor is successfully converted into silica sols that are deposited on the surface of the spherical polymer nanoparticles. Thin film membranes are then prepared from these silicified spherical particles (hard spheres) as well as the initial spherical particles devoid of silica coating (soft spheres). These membranes are fully characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and water filtration test.

Polymerizations by RAFT: Developments of the Technique and Its Application in the Synthesis of Tailored (Co)polymers

“…Unexpectedly, the presence of the silica layer not only altered the pore size but also enhanced the mechanical robustness of the prepared thin film membranes (as compared to the uncoated particles). [ 256 ]…”

Experimental Design in Polymer Chemistry—A Guide towards True Optimization of a RAFT Polymerization Using Design of Experiments (DoE)

“…RAFT is one of the most powerful and versatile controlled radical polymerization techniques [ 11 ] for the synthesis of complex multiblock architectures [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ] as well as so-called “smart” materials, such as switchable filtration devices [ 19 , 20 , 21 ] or nanocarriers for biomedical applications [ 22 , 23 , 24 ]. Within this group of “smart” materials, especially upper critical solution temperature polymers, such as this work’s optimization target polymethacrylamide (PMAAm) [ 25 , 26 ], have received increasing attention [ 27 , 28 , 29 , 30 ].…”

RAFT dispersion polymerisation of lauryl methacrylate in ethanol–water binary mixtures: synthesis of diblock copolymer vesicles with deformable membranes

“…This problem is well documented for various RAFT alcoholic dispersion formulations. [21][22][23][24][25][26][27][28][29][30] In this context, Zhang et al reported the effect of adding water to the RAFT alcoholic dispersion polymerisation of benzyl methacrylate on the final copolymer morphology. 21 Using just 5 % water as a co-solvent enabled either spheres, worms or vesicles to be obtained when increasing the target degree of polymerisation (DP) of the coreforming PBzMA block.…”