Solvent-controlled synthesis of hydrophilic and hydrophobic carbon dots.

Abstract

Hydrophilicity and hydrophobicity are of paramount importance in surface chemistry. In this study, a solvent-controlled synthesis of hydrophilic and hydrophobic carbon dots (CDs) was prepared via a solvothermal process using pentafluorobenzyl alcohol as the carbon source in either deionized water or N,N-dimethylformamide (DMF) medium. By simply varying the reaction solvent to control the doping of nitrogen and fluorine elements, the hydrophilicity or hydrophobicity of the CDs could be regulated. Hydrophobic and hydrophilic CDs showed blue and green light under a UV lamp, respectively. Besides, we regulated the volume ratio of water/DMF (1 : 2, 1 : 1 and 2 : 1) in the reaction solvent to prepare amphiphilic CDs and further studied their hydrophilicity and hydrophobicity. Furthermore, the sensitivity of hydrophobic CDs to water was investigated. In water detection, the photoluminescent intensity of the blue peak and green peak showed high linearity within the water content of 4-80% and 10-80%, respectively (limit of detection = 0.08%, v/v, in DMF).