In this work, we explored a direct way of labeling poly(N-isopropylacrylamide) (PNIPAm) and developed a fluorescent thermometer with desired feature of aggregation-enhanced emission. A fluoranthene-based biphenol polymer, PNIPAm-MAh-4 (PN4), consisting of N-isopropylacrylamide (NIPAm) and 4-(9-(2-(4-hydroxyphenyl)ethynyl)-7,10-diphenylfluoranthen-8-yl)-phenol (4) units as temperature-responsive and fluorescent signaling parts, respectively, was synthesized. The aqueous solution of PN4 exhibits weak fluorescence (FL) below 30 degrees C, whereas shows FL enhancement above 30 degrees C. The FL intensity increases with temperature monotonically until 50 degrees C, and the maximum FL intensity at 50 degrees C is about 7-fold higher than that at 15 degrees C. The FL enhancement is found to be associated with a heat-induced polymer chain conformation transition from hydrated coil to dehydrated globule. And the possible mechanisms for emission responses of PN4 against temperature, concentration and aggregation are suggested, respectively. The plausible mechanism of the sensitivity of the emission intensity to temperature or polymer state involves the deprotonation equilibrium and formation of the less fluorescent form of PN4. Meanwhile, the polymer possesses high reversibility of the FL response. Therefore the polymer PN4 is expected to have great potential as a fluorescent thermometer with high sensitivity and reversibility, and our work explores its utilities in molecular probes, biotechnology, multistimuli-responsive nanomaterials and smart polymer machines. (C) 2013 Elsevier B.V. All rights reserved.