Click‐Engineered 1,2,3‐Triazole‐Tethered Polyurethanes: Molecular Design, Structure‐Property Relationships, and Potential Antifouling Behavior

ABSTRACT

A compelling strategy to integrate contact‐active, non‐leaching functionalities directly within the polyurethane (PU) backbone is the covalent incorporation of heterocyclic structures. To investigate the influence of triazole‐based molecular architecture on polyurethane properties, triazole‐based dihydrazide chain extenders bearing C8 and C12 pendant alkyl chains were synthesized via Cu(I)‐catalyzed azide‐alkyne cycloaddition and incorporated into thermoplastic polyurethanes (TPUs). Thermal analysis revealed composition‐dependent stability governed by the interplay of triazole incorporation, side‐chain length, hard‐segment content, and diisocyanate structure. Systematic variation of pendant alkyl chain length, polyol molar mass, diisocyanate structure, and NCO/OH ratio demonstrated that molecular architecture governs molar mass distribution, microphase separation, storage modulus, and glass transition behavior. Increasing hard‐segment content and hydrophobic triazole substituents progressively increased surface hydrophobicity, with water contact angles reaching approximately 115°. Antimicrobial evaluation against Escherichia coli (Gram‐negative), Staphylococcus aureus (Gram‐positive), and Candida albicans (fungal strain) demonstrated reduced microbial adhesion on triazole‐functionalized TPU surfaces despite the absence of diffusional antimicrobial activity, indicating non‐leaching, contact‐active antifouling behavior. Furthermore, an optimized formulation yielded a preliminary waterborne dispersion that formed mechanically robust free‐standing films, demonstrating the feasibility of future environmentally friendly waterborne polyurethane coating systems.