Revolutionizing photocatalysis: Synthesis of innovative poly(N-tertiary-butylacrylamide)-graft-hydroxypropyl cellulose polymers for thermo-responsive applications via metal-free organic photoredox catalysis

• Published in: International journal of biological macromolecules 2025-02, Vol.288, p.138775, Article 138775
• Main Authors: Iqbal, Muhammad Asif, Younis, Muhammad Wasim, Maqbool, Muhammad, Goh, Hui Hwang, Kurniawan, Tonni Agustiono, Amjad, Muhammad, Othman, Mohd Hafiz Dzarfan
• Format: Article
• Language: English
• Subjects: Lower critical solution temperature (LCST); Macroinitiator (HPC-1); O-ATRP
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.138775

In this study, we present a groundbreaking approach utilizing metal-free, visible light-mediated organic photoredox catalyzed atom transfer radical polymerization (O-ATRP) to synthesize cellulose-based stimuli-responsive polymers. Our method resulted in the successful synthesis of innovative metal-free poly(N-tertiary-butylacrylamide)-graft-hydroxypropyl cellulose (PNTBAM-g-HPC) polymers with exceptional control over molecular weight and narrow dispersity index (Đ) and explored their applications in organo-photocatalytic reactions. This approach addresses the limitations of traditional atom transfer radical polymerization method, which suffer from metal contamination and toxicity related problems. O-ATRP and organic photoredox catalysts have been sought to address these difficult challenges. In this study, we synthesized organic compound; 2,4,5,6-tetrakis(diphenylamino)isophthalonitrile (4DPIPN), which served as an organic photoredox catalyst, enabling the synthesis and application study of PNTBAM-g-HPC polymers via organic photoredox catalysis. Furthermore, by employing 4DPIPN, three different types of PNTBAM-g-HPC polymers were synthesized. Through thorough characterization techniques including FTIR, NMR, UV/Visible spectroscopy, TGA, and GPC analysis, we confirmed the successful synthesis of photocatalyst and three different types of PNTBAM-g-HPC polymers under O-ATRP conditions. By adjusting the molar ratios of PNTBAM side chains, we fine-tuned the LCST of HTA-20 polymers to 37.3 °C, demonstrating their thermoresponsive behavior. This synthetic approach shows great potential for applications in biosensors, pharmaceuticals, biomedical engineering, and drug delivery systems. [Display omitted] •Synthesis of innovative PNTBAM-g-HPC stimuli responsive polymers via metal free visible light mediated organic photoredox catalyzed atom transfer radical polymerization with best control over molecular weight and narrow dispersity index (Đ)•Physiological temperature of 37.3°C for HTA-20 polymers•LCST values for the HTA-10 and HTA-15 polymers were 41.6°C and 39.7°C•Functional materials with tailored properties for practical applications