Temperature Responsive Electrocatalysis Based on Poly(N-isopropylacrylamide) Modified Graphene Oxide.

Poly(N-isopropylacrylamide) modified graphene oxide (PNIPAm-GO), which is a type of thermal responsive GO, was designed and synthesized via a covalent strategy of 'grafting-from'. The as prepared modified nanosheets well integrated the individual advantages of two components, such as the thermal sensitivity of PNIPAm-terminal and the conductivity, the open 2D structure of GO substrate. PNIPAm-GO could well perform the reversible regulation of hydrophilicity/hydrophobicity in aqueous solution upon the variation of temperature signal. Such unique property can also lead to the utilization of PNIPAm-GO as intelligent electrode material to achieve switchable electrochemical response toward [Fe(CN)6]3-/4- probe. In comparison with PNIPAm/GC electrode without GO, PNIPAm-GO/GC electrode could exhibit better electrochemical performance of 'ON/OFF' switching effect due to the intrinsic property and large surface area of introduced GO. Moreover, it was found that the PNIPAm-GO/GC electrode also displayed excellent thermal responsive electrocatalysis toward the detection of 1,4-dihydro-β-nicotinamide adenine dinucleotide (NADH) and dopamine (DA), which enabled the achievement of two different catalytic status on one same electrode. Such switchable catalytic performance of PNIPAm-GO/GC electrode may greatly enhance the flexibility of its application, and thus it is expected to have widely potential applications in the fields of biosensors and biocatalysis.