Synthesis of nanostructured materials for biosensor and fuel cell applications
Description
Nanotechnology has attracted the attention of many different fields due to the new and exiting possibilities it entails. However, the future of nanotechnology depends on (i) the successful understanding and discovery of material properties at the nanoscale, (ii) efficient manufacture of nanoscale materials, and (iii) most importantly, incorporation of nanomaterials into real world applications and devices. The purpose of this research is to synthesize macroscale materials for applications such as fuel cell membranes or biosensors by assembly or modification at the nanoscale This research is concentrated in two main projects. The first project focuses on the direct synthesis of a PEEK fuel cell membrane from sulfonated monomers with nanoscale features. S-PEEK membranes were evaluated for possible fuel cell applications by determining the degree of sulfonation, water swelling, proton conductivity, methanol diffusivity and thermal stability. As synthesized S-PEEK membranes exhibit conductivities (25°C) from 0.02--0.07 S/cm, water swelling from 13--54%, ion-exchange capacities (IEC) from 0.7--1.5 mmol/g and methanol diffusion coefficients from 3 x 10-7 --5 x 10-8 cm2/s at 25°C. These diffusion coefficients are much lower than that of NafionRTM (2 x 10-6 cm2/s), making S-PEEK membranes a good alternative to reduce problems associated with high methanol crossover in direct methanol fuel cells The second project consists of synthesizing (2D) or (3D) nanowire thin film Pt electrodes for applications as glucose sensors. Although platinum nanowires have shown to have unique properties, it is still challenging to fabricate nanowire devices such as sensors. This research reports the fabrication of platinum nanowires into continuous thin film electrodes and the application as biosensors. The electrodes were synthesized by the following steps: (1) construction of a nanostructured mesoporous thin film template by self-assembly of surfactant and silicate species, (2) electrodeposition of platinum within the pores of the silica template, (3) removal of the silica template, and (4) immobilization of the enzyme on the platinum electrodes. SEM, TEM, chronoamperometry and cyclic voltammetry were used to characterize the electrodes. The sensor sensitivity was determined amperometrically. The sensors show improved sensitivities and stabilities, providing a promising approach to integrate nanowires into useful devices