Aza-Based Donor-Acceptor Conjugated Polymer Nanoparticles for Near-Infrared Modulated Photothermal Conversion

Abstract

It is highly desired that synthesis of photothermal agents with near-infrared (NIR) absorption, excellent photostability, and high photothermal conversion efficiency are essential for potential applications. In this work, three (D-A) conjugated polymers ( PBABDF-BDTT, PBABDF-BT , and PBABDF-TVT ) based on aza-heterocycle, bis(2-oxo-7-azaindolin-3-ylidene)benzodifurandione (BABDF) as the strong acceptor, and benzodithiophene-thiophene (BDTT), bithiophene (BT), and thiophene-vinylene-thiophene (TVT) as the donors, were designed and synthesized. The conjugated polymers showed significant absorption in the NIR region and a maximum absorption peak at 808 nm by adjusting the donor and acceptor units. Their photothermal properties were also investigated by using poly(ethylene glycol)-block-poly(hexyl ethylene phosphate) (mPEG-b-PHEP) to stabilize the conjugated polymers. Photoexcited conjugated polymer ( PBABDF-TVT ) nanoparticles underwent non-radiative decay when subjected to single-wavelength NIR light irradiation, leading to an excellent photothermal conversion efficiency of 40.7%. This work indicated the aza-heterocycle BABDF can be a useful building block for constructing D-A conjugated polymer with high conversion efficiency.

Isoindigo‐Based Dual‐Acceptor Conjugated Polymers Incorporated Conjugation Length and Intramolecular Charge Transfer for High‐Efficient Photothermal Conversion

“…mD and cD are the mass and heat capacity of the DI water used to disperse the CP NPs, respectively. [47,56] Near-Infrared (NIR) Imaging of Polymer Nanoparticles: The P-IIG-EDOT-BT NPs (P-IIG-EDOT-BT NPs) and P-IIG-DPP NPs (P-IIG-DPP NPs) at different concentrations in 1.5 mL microcentrifuge tubes were irradiated with an 808 nm laser at 1.0 W cm −2 for 10 min.…”

“…mD and cD are the mass and heat capacity of the DI water used to disperse the CP NPs, respectively. [ 47,56 ]…”