Open AccessCharacteristics of Solid-State Calcium Ion Sensors Based on Photocurable and Selfplasticising Polyacrylate Matrices
Author(s) -
Lee Yook Heng,
Elizabeth A. H. Hall
Publication year - 2017
Publication title -
asean journal on science and technology for development/asean journal on science and technology for development
Language(s) - English
Resource type - Journals
eISSN - 2224-9028
pISSN - 0217-5460
DOI - 10.29037/ajstd.115
Subject(s) - membrane , selectivity , calcium , ionophore , potentiometric titration , acrylate , chemistry , polymer , chemical engineering , ion , materials science , inorganic chemistry , copolymer , organic chemistry , biochemistry , engineering , catalysis
New membrane materials based on cross-linked poly(n-butyl acrylate) (nBA), have been used successfully as calcium ion-selective membranes. These membrane materials possess selfplasticising property and hence do not require plasticisers. The photocurability and good adhesion characteristics of these polymer matrices enable workable solid-state calcium ion sensors to be fabricated by simple photocure procedures employing the calcium ionophore ETH5234 and a lipophilic additive as ion sensing components. The calcium ion-selectivity of the sensors can be controlled by varying the chemical composition of the photocured membrane. An optimum amount of the cross-linker 2,2-hexanedioldiacrylate (HDDA) and the incorporation of n-heptyl acrylate (nHA) led to improvement in the calcium ion-selectivity. The best calcium ion-selectivity was obtained from a copolymer membrane with composition: nBA = 74 wt-%, nHA = 20 wt-% and HDDA = 0.1 wt-%. The selectivity coefficients of calcium over major cations were: LogKCaPot,Na= -4.4, LogKCaPot,K = -3.6, LogKCa,PotLi = -5.9, LogKCaPot,Mg= -4.4 with a Nernstian slope (29.1 ± 0.8 mV/decade) under buffered conditions. This potentiometric performance is comparable to other solid-state calcium ion sensors with various plasticised polymer membranes.