# Recyclable IPN Photocatalysts Supported by Polymer Matrices: From Soluble Copolymers to Core-Polymer Brush Shell Nanostructures

## TL;DR

This paper explores how polymer supports affect the performance and recyclability of photocatalysts, showing that nanostructured supports enable efficient reuse.

## Contribution

A new strategy for enhancing photocatalyst recyclability using nanostructured polymer supports is introduced.

## Key findings

- Soluble copolymers showed catalytic activity but limited recovery.
- Nanostructured polymer brushes enabled ≥90% catalyst recovery and reuse.
- Polymer architecture critically influences catalytic performance and sustainability.

## Abstract

Functional polymeric materials have recently emerged
as promising
supports for organic photocatalysts (PCs), yet the effects of PC design
and polymer architecture on catalytic performance remain underexplored.
In this study, we present a versatile strategy for small-molecule
activation using carbazolyl-dicyanobenzene-based PCs featuring an
isophthalonitrile (IPN) core. These PCs feature thermally activated
delayed fluorescence (TADF) properties and long-lived excited states,
although they also suffer from an intrinsic chemical fragility that
hampers their recyclability. A library of IPN derivatives was synthesized,
characterized, and integrated into either soluble copolymers (by exploiting
controlled radical polymerization) or grafted from inert silica nanoparticles
(NPs) to yield PC-loaded spherical polymer brushes. Although soluble
copolymers showed catalytic activity comparable to that of free PCs
while testing model Povarov-type cycloadditions, PC recovery was only
modest and relied on precipitation steps. In contrast, PC-loaded brushes
on NPs achieved high yields and enabled efficient catalyst recovery
and reuse (≥90%) over multiple cycles. This comparative approach
highlights how the nature of the polymeric support, soluble vs. nanostructured, critically influences both catalytic
performance and recyclability. More generally, the incorporation of
IPN PCs into advanced polymer scaffolds is demonstrated to enhance
their applicability, cost-efficiency, and sustainability.