Molecularly imprinted polymer–Ag2S nanoparticle composites for sensing volatile organics

Ghulam Mustafa,Peter A Lieberzeit

doi:10.1039/c3ra44208j

Abstract

Polyurethane-based molecularly imprinted polymers (MIP) and Ag2S nanoparticles (NP) form a nanocomposite that is suitable for detecting vapours of aliphatic alcohols with quartz crystal microbalance (QCM) sensors. The resulting sensor responses are almost three times higher than the average response of its two constituents: the composite leads to a normalized response of −70 Hz towards 400 ppm 1-butanol vapour in air, which is two times more than for a pure NP layer of the same thickness and four times higher than the response of the MIP. Furthermore, the MIP leads to structural selectivity that strongly prefers 1-butanol over 2-butanol due to the branched structure of the latter. Selectivity reaches a factor of almost five.

Highlights

It is well-known that the properties of nanomaterials substantially differ from those of the respective bulk matrix
Polyurethane-based molecularly imprinted polymers (MIP) and Ag2S nanoparticles (NP) form a nanocomposite that is suitable for detecting vapours of aliphatic alcohols with quartz crystal microbalance (QCM) sensors
A somewhat similar approach mixes gold nanoparticles coated with electropolymerized chitosan and graphene, respectively, to electrochemically detect erythromycin.[34]. In both cases the nanoparticles blended into the matrix can be regarded as an indicator helping to detect changes in the matrix during recognition. In contrast to this we aim at blending metal sul de nanoparticles with molecularly imprinted polymers (MIP) as shown in Fig. 1 to assess whether the composite “just” leads to combined recognition properties or whether the whole material can be regarded more than the sum of its parts when applying it as a sensitive material to detect vapours of aliphatic alcohols

Summary

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Imprinted polymer–Ag2S nanoparticle composites for sensing volatile organics. Polyurethane-based molecularly imprinted polymers (MIP) and Ag2S nanoparticles (NP) form a nanocomposite that is suitable for detecting vapours of aliphatic alcohols with quartz crystal microbalance (QCM) sensors. The resulting sensor responses are almost three times higher than the average response of its two constituents: the composite leads to a normalized response of À70 Hz towards 400 ppm 1-butanol vapour in air, which is two times more than for a pure NP layer of the same thickness and four times higher than the response of the MIP. The MIP leads to structural selectivity that strongly prefers 1-butanol over 2-butanol due to the branched structure of the latter. Selectivity reaches a factor of almost five

Introduction

Results and discussion

Sensor characteristics

Conclusions