Two series of polyurethanes (P1-P10) containing NLO chromophores as side chains were prepared, in which the size of isolation groups was changed from small atoms to much larger groups such as carbazolyl groups. The polymers were well characterized. The tested NLO properties of the polymers demonstrate that the NLO values and the poling efficiency of the polymers are not always improved with increasing of the size of isolation spacer, and for a given chromophore moiety, there is a suitable isolation group present to boost its microscopic â value to possibly higher macroscopic NLO property efficiently.

For the first time, a conjugated fluorescent polymer was utilized to probe R-amino acids, sensitively and selectively, through a new approach. First the strong fluorescence of the prepared polyfluorene (P1) was quenched by trace copper ions, and then the quenched fluorescence was recovered upon the addition of R-amino acids, making P1 a new and sensitive biosensor toward R-amino acids. The experimental results demonstrated that the R-amino acid selective nature of P1 over other analytes was relatively good. Thus, the work reported here might open up a new avenue for developing new biosensors.

For the first time, a series of dendronlike main-chain polyurethanes have been successfully designed and synthesized, in which different isolation groups with different sizes were introduced to modify the subtle structure of the used "H"-type chromophores, according the concept of "suitable isolation groups". Thanks to the advantages of "H"-type chromophores and the introduced suitable isolation group, all of the polymers demonstrated large NLO effects, good processability, improved optical transparency, and thermal stability. The obtained experimental results indicated that the utilization of "H"-type chromophores might be a promising choice to efficiently translate the large-values of the organic chromophores into high macroscopic NLO activities of polymers.

By applying an indirect strategy, a new rhodamine-based dye (I) was successfully developed as a colorimetric chemosensor for the sensitive detection of cyanide. In the presence of copper ions, the colorless solution of compound I changed to magenta; however, upon the addition of trace cyanide, the magenta color faded to colorless immediately, with a detection limit as low as 0.013 ppm (ΔA) 0.054), much lower than the Maximum Contaminant Level for cyanide in drinking water (0.20 ppm) set by the US Environmental Protection Agency. Other anions, including Cl-, I-, IO3-, SO4 2-, NO2-, Br-, H2PO4-, F-, SCN-, HSO4-, and ClO4-, had nearly no influence on the probing behavior of dye I toward cyanide.