Onion-like structure block copolymers

Besides the well-known core-shell and inverse core-shell [60], or acorn and Janus morphologies obtained with polymers with similar polarities [33], other interesting structures can be formed. Half-spherical structures are accessible by removing the liquid in acorn structures formed with a polymer and a liquid [40, 61]. Onion-like structures are created from block copolymers, for which the phase separation into lamellae causes layered structures that follows the curvature of the particle where they are confined [37,40,62]. The diameter of the particle is in this case also very important. Indeed, if the particle size is low enough, core-shell or Janus stmctures can be obtained [40]. A large variety of different stmctures were predicted from simulations on diblock copolymer/homopolymer blends [63], star-triblock copolymers in spherical nanopores [64], or on diblock copolymers under different confinements [65-67], among which several have already been prepared... 

Fig. 1 Schematic representation of co-assembly of two oppositely charged ionic-neutral diblock copolymers in water into complex coacervate core micelles, in short C3Ms, with a core comprising the oppositely charged monomers surrounded by a shell of neutral, water-soluble monomers. The two monomer types in the corona may mix left) or segregate radially (mid-left), laterally (mid-right) or both radially and laterally (right) depending on the chemical composition of the block copolymers and hence the miscibility and differential solvent quality of the neutral monomers. This may lead to the formation of onion-like micelles, also known as core-shell-corona structures (mid-left), Janus micelles (mid-right) or patchy micelles, also known as raspberry-like micelles (right). Figure from Ref. [188]...

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