Thoedtoon ChampaiboonGamolwan TumcharernAnupat PotisatityuenyongSumrit WacharasindhuMongkol SukwattanasinittChulalongkorn UniversityThailand National Science and Technology Development AgencyMahidol University2018-09-132018-09-132009-06-04Sensors and Actuators, B: Chemical. Vol.139, No.2 (2009), 532-537092540052-s2.0-66349085323https://repository.li.mahidol.ac.th/handle/123456789/27558A blue-colored polyelectrolyte multilayer (PEM) film of poly(10,12-pentacosadiynoic acid), or poly(PCDA) vesicles, was successfully prepared by layer-by-layer deposition with polycationic chitosan, and its application as a colorimetric chemo-sensor for water soluble aromatic compounds was investigated in comparison to the same poly(PCDA) vesicles as a liquid sol. The color of the PEM film changes from blue to red within 5 min when immersed into 10 mM α-cyclodextrin (α-CD) solution giving the colorimetric response (CR) of ∼65%. The α-CD induced color transition of the PEM film was completely inhibited in the presence of 10 mM of either benzoic acid or 4-nitrophenol, which represents a 1:1 mole ratio of aromatic compound:α-CD, showing nearly zero percent CR and the film remained blue. In contrast, only partial inhibition was observed by eyes in the presence of 20 mM 4-methoxyphenol and indole as the film appeared purple with ∼15% CR. Phenol and nitrotoluene did not show inhibition detectable by naked eyes but the low level of inhibition, ∼35% CR remained, was observed spectroscopically at 20 mM. For nitrophenols, the degree of inhibition is varied by the isomeric structures in the following order: 4-nitrophenol > 3-nitrophenol > 2-nitrophenol. The competitive inclusion of the aromatic compound into the α-CD cavity is probably responsible for the observed inhibition of color transition. Compared with the liquid sol of poly(PCDA) vesicles, the PEM film, as a solid sol, offers less color interference from turbidity and intrinsic color of the samples being analyzed that the results of inhibition can be readily justified by naked eyes. © 2009 Elsevier B.V. All rights reserved.Mahidol UniversityEngineeringMaterials SciencePhysics and AstronomyArticleSCOPUS10.1016/j.snb.2009.03.047