Sensors and Actuators B 143 (2010) 789–794 Contents lists available at ScienceDirect Sensors and Actuators B: Chemical journal homepage: www.elsevier.com/locate/snb Short communication Polydiacetylene-based colorimetric sensor microarray for volatile organic compounds Hao Jiang, Yali Wang, Qiang Ye, Gang Zou ∗ , Wei Su, Qijin Zhang CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, Key Laboratory of Optoelectronic Science and Technology in Anhui Province, University of Science and Technology of China, Hefei, Anhui 230026, PR China article info Article history: Received 6 May 2009 Received in revised form 27 September 2009 Accepted 30 September 2009 Available online 9 October 2009 Keywords: Polydiacetylene Solvatochromism Colorimetric sensor microarray Soft lithography abstract The development of a novel polydiacetylene (PDA)-based sensitive colorimetric microarray sensor for the detection and identification of volatile organic compounds was reported. The organic solvent-dependent colorimetric responses of PDA-embedded polymer matrix had been investigated in detail, which allowed for a straight forward “color pattern” procedure to differentiate among common organic solvents. Fur- ther, multi-layer PDA-based micro patterns had been fabricated by a sol–gel process combined with the soft lithography method. The structures of multi-layer PDA-based micro patterns were characterized by scanning electron microscopy (SEM). The organic solvent-dependent fluorescence changes of PDA- based micro patterns had been investigated in detail. Excellent differentiation of organic compounds can be achieved based on cross-responsive array sensor and these systems aim to mimic the mammalian olfactory system by producing composite responses unique to each odorant. © 2009 Elsevier B.V. All rights reserved. 1. Introduction The efficient monitoring of volatile organic compounds (VOCs) has gained prominence in environmental and public safety con- trol due to the potential health hazards posed by exposure to these substances. Indeed, the development of efficient sensors for the detection of VOCs has become the subject of intensive study [1–3]. Changes in electrochemical, conducting, optical and fluorescence properties of sensor matrices engendered upon exposure to VOCs have served as the output signals. Suslick and co-workers reported that the development of colorimetric sensor array system was par- ticular important because of its effectiveness and simplicity [4,5]. Diverse VOCs can be monitored in this system owing to VOC- induced color changes of sensors that are composed of arrays of metalloporphyrins, solvatochromic dyes, and pH indicators [4–7]. Kim and co-workers developed a new strategy for colorimetric and specific detection of VOCs that was based on conjugated polydi- acetylene (PDA)-embedded solvatochromic electrospun fibers [8]. PDAs exhibit intense chromatic switch from blue to red in response to external stimuli and these colorimetric changes can be easily per- ceived by UV–vis absorption spectrum, fluorescence or even the naked eyes [9–14]. Owing to the readily detectable color changes that PDAs undergo upon environmental perturbation, the signif- icance of the different fluorescence properties of PDAs has been ∗ Corresponding author. Tel.: +86 551 3601698; fax: +86 551 3601704. E-mail address: gangzou@ustc.edu.cn (G. Zou). nearly ignored from the perspective of sensor applications. And the fluorescence properties of PDAs, when combined with modern methods for the fabrication of microarrays, should stimulate the development of a number of new label-free chemo sensor systems [15–18]. Array-based vapor sensing has emerged as a potentially power- ful approach toward the detection of chemically diverse analytes. Based on cross-responsive sensor elements, rather than specific receptors for specific analytes, these systems produce compos- ite responses unique to an odorant in a fashion similar to the mammalian olfactory system [19]. A distinct pattern of responses produced by the array provides at least the possibility of a char- acteristic fingerprint for each analyte. Thus, the combination of the novel colorimetric properties of PDA and the merits of micro- pattern technique will serve as the basis for a unique and practical application of the PDA conjugated polymers to the detection of VOCs. In this paper, organic solvent-dependent colorimetric responses of PDA-embedded polymer matrix films have been investigated, which allow for a straightforward “color pattern” pro- cedure to differentiate among common organic solvents. Further, the organic solvent-dependent fluorescence changes of multi-layer PDA-based micro patterns fabricated by a sol–gel process com- bined with the soft lithography method have been characterized in detail. This work not only develops a new strategy for the colorimet- ric and specific detection of VOCs based on PDA microarrays, but also is of great value for the general-purpose vapor dosimeters and analyte-specific detectors (for insecticides, drugs or neurotoxins, for example). 0925-4005/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.snb.2009.09.063