Lauric Diacid‐Derived Sulfur‐Decorated Functional Polymers Displaying Programmable Thermal and Unconventional Luminescence Properties by Simple Thionation

Aliphatic polythioesters (featuring the (C═O)─S linkage) are recognized as useful complements to polyesters that possess intriguing properties, such as high optical features, metal coordination ability and affinity for metal surfaces, self‐healing capability, and improved crystallinity amongst others. Still, conventional synthetic approaches often require the use of toxic acyl chlorides. Thus, in this study, two semi‐crystalline polythioesters, P1 and P2 , were synthesized via a step‐growth polycondensation between a long‐chain bioderived diacid (1,12‐dodecanedioic acid, aka lauric diacid) and two commercially available dithiols, namely, 1,6‐hexanedithiol or 2,2’‐(ethylenedioxy)diethanethiol). The activation was achieved using 1,1’‐carbonyldiimidazole, which eliminates the need for acyl chlorides and leads to the formation of a useful by‐product, 1,8‐diazabicycloundec‐7‐ene imidazolium salt. An exemplary polythioester (i.e., P2 ) underwent a previously less‐reported post‐polymerization modification (hereafter referred to as modification, for clarity) with Lawesson's reagent to yield polydithioester PP2 . This transformation induced a distinct change in material behavior, converting a semi‐crystalline structure (melting temperature: 67.7°C) into an amorphous one characterized by a glass transition temperature of −40°C, and significantly reducing its luminescent response. Thus, this study provides a more sustainable synthetic platform for the development of functional polythioesters with tunable thermal and optical properties.