Facile Control of Molecular Weight Distribution via Droplet‐Flow Light‐Driven Reversible‐Deactivation Radical Polymerization^†

Abstract

Comprehensive SummaryMolecular weight distribution (MWD) is fundamental for polymer analysis, which influences many important properties of polymeric materials. In this work, we demonstrate the development of a computer‐aided droplet‐flow system that combines photo‐mediated reversible‐deactivation radical polymerization (RDRP) and chain transfer agent (CTA) diffusion strategy to enable facile MWD control for the first time. Synthetic advantages of this photo‐flow polymerization allow controlled chain‐growth to yield a variety of polymers of tunable MWDs in a broad range (Ð ≈ 1.1—1.9) with predetermined molecular weights (Mn ≈ 4—30 kDa) and good chain‐end fidelity. Notably, the computer‐aided platform has streamlined an automatic and high‐throughput pathway to prepare polymer libraries of tunable MWDs. For copolymers, chemical compositions could be readily regulated besides MWDs with the droplet‐flow platform. We believe that this work should be attractive for polymer engineering, and informative to create more flow polymerization techniques toward on‐demand control of diverse polymer characters.

Unleashing the Power of PET-RAFT Polymerization: Journey from Porphyrin-Based Photocatalysts to Combinatorial Technologies and Advanced Bioapplications

“…This method facilitated the production of polymer mixtures that possessed a customized MWD as well as enabled the creation of copolymer mixtures with composition gradients that were tailored to specific needs. A computer-aided droplet-flow system was developed using PET-RAFT polymerization and droplet-flow polymerization to enable easy control of MWD in polymer synthesis . This technique offered synthetic benefits in achieving adjustable MWDs, predetermined molecular weights, and reliable chain-end fidelity.…”

“…A computer-aided droplet-flow system was developed using PET-RAFT polymerization and droplet-flow polymerization to enable easy control of MWD in polymer synthesis. 117 This technique offered synthetic benefits in achieving adjustable MWDs, predetermined molecular weights, and reliable chainend fidelity. The computer-aided platform also enabled the automatic and high-throughput generation of polymer libraries with diverse MWD and chemical compositions.…”

Tuning Polymer Molecular Weight Distribution in Cationic RAFT Polymerization by Mixing Chain Transfer Agents†

“…[ 1‐4 ] However, efficient methods to precisely tune the polymer MWD in cationic polymerization haven't been well explored, which is essential for polymer properties such as mechanical properties, crystallization behavior, and viscoelasticity. [ 5‐7 ] In fact, it was until recent years some efficient strategies to tune polymer MWD have been developed such as metered additions of initiating species in controlled polymerization, [ 8‐9 ] blending polymers directly, [ 10‐12 ] or through combination with flow chemistry, [ 13‐18 ] tuning the components of the polymerization systems, [ 19‐26 ] and adjusting the external stimulus. [ 27‐34 ] In terms of cationic polymerization, Aoshima et al .…”

Flow Optimization of Photoredox-Mediated Metal-Free Ring-Opening Metathesis Polymerization

“…In the case where one fluid is the reaction solution and the other fluid is a gas, the gas composition of the reaction solution can be maintained within the flow loop, thereby allowing one to probe the interaction of the atmosphere with a reaction. For polymerizations, droplet flow setups have been shown to yield experimental results (like molecular weight dispersity, monomer conversion, and initiation efficiency) better than that of continuous flow setups and comparable to that of small-scale batch setups owing to more similar mixing dynamics to that of batch. , Droplet flow setups have also shown great compatibility with photocontrolled radical polymerizations (CRPs; Figure b). , …”

“…66,67 Droplet flow setups have also shown great compatibility with photocontrolled radical polymerizations (CRPs; Figure 1b). 70,71 The droplet flow setup is more complex than its continuous flow counterpart. Pressure regulators, flow controllers, and other safety measures are essential to creating a safe and controlled droplet flow setup.…”