Thermo‐Fluorescent Bactericidal Quantum Dots Based Smart Multifunctional Textiles via Molecular Surface Engineering and 3D‐Printed Interlocked Architectures

Functional textiles integrating optical activity, environmental responsiveness, and structural adaptability are essential for next-generation wearable systems. Here, we present a versatile strategy for fabricating thermo-fluorescent, UV-protective, and antibacterial smart textiles via carbon dot (CD)/polymer nanocomposite coatings. CDs synthesized hydrothermally exhibited strong excitation-dependent emission (320-460 nm), a fluorescence lifetime of 4.2 ns, and excellent photostability over 30 days. The CDs formed hydrogen-bonding interactions within a PVA/quaternized chitosan matrix and were deposited onto textiles using dip-and-dry and spray methods, followed by hexadecyltrimethoxysilane modification to impart durable hydrophobicity (water contact angle >100°). The coated fabrics maintained fluorescence under repeated mechanical deformation and showed coating-cycle-dependent emission. The functional cotton displayed thermo-responsive fluorescence (5-100°C), with enhanced emission below 37°C and quenching above this temperature. The textiles showed strong antibacterial activity, with inhibition zones of ∼17 mm (E. coli) and ∼19 mm (B. subtilis). The textiles also demonstrated notable antioxidant performance (DPPH EC₅₀ = 88.6 µg mL^- ¹; ABTS EC₅₀ = 37.1 µg mL^- ¹) and excellent UV-blocking, exceeding a 95% relative increment in UVB blocking at the highest coating level. Integration with digital light processing printing enabled mechanically interlocked hybrid architectures without compromising functionality, establishing a multifunctional platform for advanced smart textile applications.