Characteristics of Solid-State Calcium Ion Sensors Based on Photocurableand Selfplasticising Polyacrylate Matrices

Lee Yook Heng, Elizabeth AH Hall
2008 ASEAN Journal on Science and Technology for Development  
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
more » ... s 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: LogK Ca Na Pot , = -4.4, Log K Ca K Pot , = -3.6, Log Pot Li Ca, K = -5.9, LogK Ca Mg Pot , = -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. Characteristics of solid-state calcium ion sensors...
doi:10.3125/asean.v23i4.987 fatcat:2jmksimxufcnfknhlr6h4l3h64