The postpolymerization modification of block copolymers has seen a growing interest in the past decade ranging from fundamental synthesis and structure−property relationships to potential applications. The resulting side-chain-modified block copolymers can retain the properties inherent to the parent block copolymer core, while introducing side-chain functionality that can allow for a tunable handle on material properties and consequently applications. In this Perspective, we discuss different methods of postpolymerization side-chain modification of block copolymers using either covalent or noncovalent strategies. We also describe potential applications, discuss some of the challenges remaining in this area, and suggest strategies for the advancement of the field.

Dynamic covalent networks comprised of tunable thia-Michael bonds result in phase separated networks with tailorable mechanical and adaptive properties.

As demonstrated by means of DNA nanoconstructs[1], as well as DNA functionalization of nanoparticles[2-4] and micrometre-scale colloids[5-8], complex self-assembly processes require components to associate with particular partners in a programmable fashion. In many cases the reversibility of the interactions between complementary DNA sequences is an advantage[9]. However, permanently bonding some or all of the complementary pairs may allow for flexibility in design and construction[10]. Here, we show that the substitution of a pair of complementary bases by a cinnamate group provides an efficient, addressable, UV light-based method to covalently bond complementary DNA. To show the potential of this approach, we wrote micrometre-scale patterns on a surface via UV light and demonstrate the reversible attachment of conjugated DNA and DNA-coated colloids. Our strategy enables both functional DNA photolithography and multi-step, specific binding in self-assembly processes.

A triblock copolymer containing the complementary hydrogen bonding recognition pair ureidoguanosine-diaminonaphthyridine (UG-DAN) as pendant functional groups is synthesized using ring-opening metathesis polymerization (ROMP). The norbornene-based DAN monomer is shown to allow for a controlled polymerization when polymerized in the presence of a modified-UG molecule that serves as a protecting group, subsequently allowing for the fabrication of functionalized triblock copolymers. The self-assembly of the copolymers was characterized using dynamic light scattering and (1) H NMR spectroscopy. It is demonstrated that the polymers self-assemble via complementary hydrogen bonding motifs even at low dilutions, indicating intramolecular interactions.