CORRELATION OF LANGMUIR ISOTHERM, OPTICAL, SURFACE POTENTIAL AND MORPHOLOGICAL CHARACTERIZATIONS OF TWO FUNCTIONALIZED DIHYDROXYCALIXARENE FOR LEAD CATION ENTRAPMENT
The versatilities of calixarenes have been known primarily in the host-guest world. In this work, two calixarenes, namely C-DHC4 and N-DHC4, possess the same lower rim but are distinct in the upper rim. The Langmuir Isotherm and optical properties have been carried out using Langmuir–Blodgett trough and UV-Visible spectroscopy, respectively. The topographical image of the calixarenes has been observed using FESEM, and lead cation entrapments of these calixarenes have been inspected using the surface potential sensor. The isotherm graph revealed the size of each calixarene; C-DHC4 ~ 1.90 nm2 and N-DHC4 ~ 2.10 nm2. The UV-Visible result demonstrated that each calixarene has two firm absorption peaks where C-DHC4 has two broad peaks, which lie in 261 and 330 nm, while N-DHC4 has two shoulders at 275 and 282 nm. FESEM images have shown the formation of calixarene nanocluster. Further monitoring on the surface potential and effective dipole moment indicate that C-DHC4 perform significant and stable results in detecting Pb2+ cations compared to N-DHC4. This study has demonstrated that detection limit as low as 1.25 x 10-2 mM, making the ∆V and µ̝ measurements a reliable method for detecting Pb2+ ions and their potential in this nanosensor field.