Block copolymers having non-linear architectures attract recent interest due to their unique self-assembly behavior in solution. We have studied amphiphilic block copolymers having dendritic and branched architectures in their hydrophilic and hydrophobic blocks. The resulting dendritic and branched block copolymers enabled us to finely adjust their self-assembly behavior in solution, resulting in the creation of complex nanostructures including block copolymer bicontinuous cubic mesophases, which are three-dimensionally well-defined periodic porous nanostructures composed of the periodic minimal surfaces of block copolymer bilayers.<br/>The formation of block copolymer cubic mesophases requires the BCP building block to exhibit high critical packing parameter (P &gt; 1). We found that the increased interfacial area of the hydrophilic block caused by the branched architecture significantly influenced the chain stretching of the hydrophobic polymer chain, resulting in the increase of the P value without significant increase of the size of the hydrophobic block. This structural feature enabled us to synthesize block copolymers self-assembling into inverse cubic mesophases having different lattices in solution.<br/>In this report, we will detail how the control of the architecture of the block copolymer allows us to control their self-assembly behavior in solution. In particular, the effect of the chain length of the hydrophobic block on the change of the critical packing parameter of the block copolymer will be discussed. We will explain how the chain length of the hydrophobic polyisoprene block can be changed by introducing the branched architecture and the microstructure control. The resulting block copolymers with complex architectures self-assemble into unique nanostructures such as colloidal cubic mesophases (polymer cubosomes) and janus-particles (polymer acorns) in solution. We will also introduce our preliminary results of the application of these structures as elastic porous materials and templates.

Solution self-assembly of block copolymers of branched architectures

255th National Meeting (2018)

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