Device fabrication
The fabrication process of the proposed sensing element is shown
in Fig. 2(a). The starting material was a silicon substrate patterned
with gold interdigital electrode pairs and interconnects (Fig. 2(a–i)). A
PMMA cap frame was placed on the substrate to confine the prepared
PDMS prepolymer, injected using a syringe (Fig. 2(a–ii)). The
prepolymer was composed of hexane, PDMS (Sylgard 184A, Dow
Corning), curing agent (Sylgard 184 B, Dow Corning), MWCNTs
(30 nm in diameter, 30 μm in length, Golden Innovation Business Co.,