Macromolecular Synthesis

Discrete Oligomers

Recently, our group developed a versatile strategy that allows access to discrete oligomers from commercially available monomer families (e.g. styrenes, acrylates, methacrylates etc.) on multigram scale. By combining high yielding, controlled polymerization procedures with automated chromatography techniques, functional oligomers can be rapidly and reproducibly accessed with NMR, MALDI, and SEC characterization demonstrating structural purity. A primary focus of the group is to compare discrete polymers with their disperse analogues to better understand and improve existing phenomena including optical properties of conjugated oligomers, crystallization behaviour of stereochemically enriched oligomers and block co-oligomer bulk and solution self-assembly.

Light-mediated controlled radical polymerization (including solution and surface chemistry)

The development of externally regulated reversible deactivation radical polymerization has seen burgeoning interest over recent years. Light, in particular, has received a lot of attention due to its low cost, ubiquity and ability to control polymer chain growth temporally and spatially. In 2012 our group discovered the light mediated polymerization of methacrylates utilizing an iridium photo-catalyst, which was subsequently employed to catalyze the controlled polymerization of acrylates. In order to circumvent the limitation of employing metals, our group then developed the first example of metal free ATRP, catalyzed by a range of novel organic photoredox catalysts. Currently, a main focus of the group is to take advantage of light mediated polymerizations (iridium, copper or fully organic catalyzed) to enable new applications at the interfaces of material, polymer and chemical sciences.

Polymer Transformations

The versatile and high yielding functionalization of polymers is critical for controlling material properties and/or for successful post polymerization reactions. Within our group we aim to develop functionalization strategies that are versatile, robust, fast, high yielding and most importantly, user friendly. For example, we have reported the transformation of a RAFT end group into a bromine atom, which facilitates a number of simple end group modifications. Both ATRP and RAFT end groups can be efficiently modified using inexpensive reagents and in the vast majority of cases, are accomplished in a “one-pot” process. Additionally, as specific end groups generated during conventional radical polymerizations are undesired for many applications, another aim of our group is to remove these by employing novel light mediated approaches.

Advanced Controlled Polymerization Methods

We are interested in developing advanced polymerization methods by combining traditional organic and polymer chemistry. For instance, we reported the synthesis of sequence defined polymers by employing relay metathesis to promote the ring opening polymerization of unstrained macrocyclic structures. Central to this approach is the development of a small molecule “polymerization trigger” which allows for the controlled, directional synthesis of a diverse range of sequence controlled polymers. On a similar note, we are also interested in advancing current polymerization protocols. ATRP, for example, typically requires various parameters to be optimized in order to achieve a high degree of control over molecular weight and dispersity. Aiming to circumvent this, we developed a set of universal conditions (same initiator, metal, ligand and solvent) capable of facilitating the controlled polymerization of acrylates, methacrylates and styrene. The facile nature of these conditions, combined with commercially available reagents, greatly expands the access and availability of tailored polymeric materials to all researchers.