Optical Response of Copolymer of 3-Aminophenylboric Acid with Aniline Film a Gainst pH

In sulfuric acid medium, on indium-tin oxide transparent conductive glass,a copolymer of 3-aminophenylboric acid and aniline film was formed by cyclic voltammetry.The characteristic absorption spectrum of this film under different pHs was determined by UV-Visible spectrometry.The film showed very high optical sensitivity against pH variation.The characteristic spectrum changed remarkably from 773nm at pH 2 to 614nm at pH 12.The corresponding titration curve was done,and the apparent pKa of this film was calculated as 6.2.The response time of copolymer film against pH is quick, and the relaxing time of the response being within 20 seconds.The reproducibility of the response was good.The characteristics and pH response showed the same when experiments were repeated,and absorption spectrum changed marginally,1.0% deviation at 773nm,and 0.7% at 614nm.