Preparation of thermoresponsive nanosheets exhibiting phase transitions in water via surface modification of layered perovskite nanosheets with poly(N-isopropylacrylamide) (PNIPAAm)

Thermoresponsive inorganic-organic hybrid nanosheets were prepared by surface modification of layered perovskite HLaNb₂O₇·xH₂O (HLaNb) wi th poly(N-isopropylacrylamide) (PNIPAAm) through surface-initiated atom transfer radical polymerization (SI-ATRP). The PNIPAAm-modified HLaNb could be exf oliated into nanosheets, which had a plate-like morphology with a thickness of ca. 25 nm. The aqueous suspension of the PNIPAAm-modified nanosheets in water exhibited phase transitions with increases in temperature to above 34°C. The nanosheets did not form precipitates when dispersed in water, even though the modified polymer chains became hydrophobic at high temperatures.