Functional single chain polymer nanoparticles

Nature creates function using well-defined, complex three-dimensional macromolecular structures. The introduction of function due to molecular arrangement is one of the great challenges in Macromolecular Science. Single chain polymer nanoparticles (SCPNs) are synthetic macromolecules that underwent intramolecular collapse through covalent and/or non-covalent interactions into 3D shapes with reasonably defined sizes and shapes, mimicking the natural biomolecules’ process. While in the past decade research on SCPNs mostly focused on synthetic pathways towards this architecture, we have started to study molecular functionality in a wide variety of potential applications in which folding provides a differential advantage compared to traditional linear and branched polymers. This work focuses on two of these applications.

Porous nanostructured carbon materials are highly interesting as potential electrode materials or electrocatalysts for energy storage applications due to their large surface area and great physicochemical stability. One promising method to prepare suitable porous nanostructured carbon materials is pyrolysis, however, the carbon precursor’s inventory is currently limited to two main class of materials, cross-linked polymers and ionic liquids. In addition, there is no clear rules on how the precursor molecular construct influences the carbon material physical properties. In this sense, SCPNs offer an interesting case, as the folded polymer can be compared to the random coils – forming two materials with the same chemical composition but different molecular pre-organization.

In SCPNs, The folding of the chains reduces their hydrodynamic volume, therefore increasing the polymer density. A major challenge in the development of alkaline fuel cells is the low chemical stability of anion exchange membranes, in which quaternary ammonium (QA) cationic functional groups are attacked by the hydroxide groups. In this work, we present a new molecular strategy to affect the kinetics of the nucleophilic attack – folding the polymer chains in order to increase the macromolecule steric hindrance on the QA. In addition, we are also studying the effect of folding on additional relevant properties such as ion conductivity and water uptake.