Poly(N-isopropylacrylamide)-tethered silicate platelets for colloidal dispersion of conjugated polymers with thermoresponsive and photoluminescence properties

Poly(N-isopropylacrylamide)-tethered nanosilicate platelets (NSP-PNiPAAm) have been synthesized by covalently bonding the polymer onto the surfaces of silicate platelets of nanometer dimension, and this class of nanohybrids has proved to be effective for dispersing water-insoluble conjugated polymers (CPs). Simple pulverization of poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV) with NSP-PNiPAAm rendered the powder material dispersible in water, whereupon it displayed thermoresponsive properties at 37.5 °C and CP particle size variation between ca. 50 and 100 nm by SEM observation. The same dispersion had a maximum UV-vis absorption at 524 nm and PL emission at 605 nm. The PL emission was significantly higher at 4 °C than at 45 °C. Being coated as a film, it showed an orange emission under an ultraviolet lamp, consistent with the PL measurement. The water-borne process of dispersing the CP in aqueous media by the presence of NSP-PNiPAAm and followed by film formation to demonstrate a unique method of manipulating hydrophobic conjugated polymers in a facile manner.