Block Copolymer Self-Assembly in Solution-Quo Vadis?

The desire to increase complexity while maintaining control over every aspect of the process itself might be used as a provocative description of the developments in block copolymer self-assembly in solution over the last decade. The community has witnessed tremendous progress, not only with regard to the design of building blocks, but also in terms of understanding assembly pathways, interfacial properties, or kinetic obstacles. In particular, the latter can be of interest (and actually turned into an advantage) if structures that are not in thermodynamic equilibrium are targeted. Within this focus review, we aim to highlight the key developments and trends that we have identified during the last five years: the development of step-wise and dynamic processes, different means to impart further hierarchy into solution-borne nanostructures, and a partial shift in focus towards gradient and bottlebrush block copolymers.