Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 5Citation - Scopus: 4Polarity Induced Vapochromism and Vapoluminescence of Polythiophene Derivatives for Volatile Organic Compounds Classification(Elsevier, 2023) Karabacak, Soner; Qun, David Lee Chao; Ammanath, Gopal; Yeasmin, Sanjida; Yağmurcukardeş, Mehmet; Palaniappan, Alagappan; Liedberg, Bo; Yıldız, Ümit HakanPolarity induced vapochromic and vapoluminescent properties of cationic poly-3-alkoxythiophene derivatives (PT) casted on polyvinylidene fluoride (PVDF) membranes are reported. PT with six different pendant groups are designed to differentially interact with volatile organic compounds (VOC) of varying polarities, thereby enabling their classification. PT exhibit a rapid vapochromic response with a concurrent modulation of vapoluminescence due to the non-covalent cation-? interactions between the pendant groups and the PT backbone. Adsorption of VOC on pendant groups alters the conformation of PT backbone, thus resulting in an increase in intensity and blue shifting of fluorescence emission within the visible spectrum. The vapoluminescent responses are found to be more sensitive with a limit of detection (LOD) of ?7 ppm and a wider dynamic range as compared to the vapochromic responses with a LOD of ?60 ppm for the detection of a model VOC: chloroform. Notably, all the PT illustrate an instantaneous recovery of colour and luminescence upon desorption of VOC. PT interaction with VOC of varying polarities was ascertained using density functional theory (DFT) and principal component analysis (PCA) methodologies. In summary, the polarity induced vapochromic and vapoluminescent properties of PT could yield a selective and sensitive vapochromic and fluorometric dual-mode VOC detection platform. © 2023Article Citation - WoS: 1Citation - Scopus: 1A Multi-Layered Graphene Based Gas Sensor Platform for Discrimination of Volatile Organic Compounds Via Differential Intercalation(Royal Society of Chemistry, 2023) Özkendir İnanç, Dilce; Ng, Zhi Kai; Başkurt, Mehmet; Keleş, Berfin; Vardar, Gökay; Şahin, Hasan; Tsang, Siu Hon; Palaniappan, Alagappan; Yıldız, Ümit Hakan; Teo, EhtSelective and sensitive detection of volatile organic compounds (VOCs) is of critical importance for environmental monitoring, disease diagnosis and industrial applications. Among VOCs, assay development for primary alcohols has captured significant research attention since their toxicity causes adverse effects on gastrointestinal and central nerve systems, resulting in irreversible blindness, and coma, and can be even fatal at high exposure levels. However, selective detection of primary alcohols is extremely challenging owing to the similarity in their molecular structure and characteristic groups. Herein, we have attempted to investigate the differential methanol (MeOH)-ethanol (EtOH) discriminative properties of single-layer, bi-layer, and multi-layer graphene morphologies. Chemiresistors fabricated using the three morphologies of graphene illustrate discriminative MeOH-EtOH responses, which is attributed to the phenomenon of differential intercalation of MeOH within layered graphene morphologies as compared to that of EtOH. This hypothesis is verified by density functional theory calculations, which revealed that the adsorption of EtOH molecules on the graphene surface is more energetically favorable as compared to that of MeOH molecules, thereby inhibiting their intercalation within the layered graphene morphologies. It is further evaluated that the degree of MeOH intercalation increases with increasing layers of graphene for obtaining differential MeOH-EtOH responses. Experimental results suggest possibilities to develop selective and sensitive MeOH assays fabricated using various graphene morphologies in a combinatorial sensor array format.Article Citation - WoS: 10Citation - Scopus: 12Tuning Pendant Groups of Polythiophene on Carbon Nanotubes for Vapour Classification(Elsevier Ltd., 2017) Tu, Meng-Che; Svm, Hari Krishna; Thilini, Alahakoon; Wallace, Lim Tse Loong; Moochhala, Shabbir; Yıldız, Ümit Hakan; Palaniappan, Al.; Liedberg, BoPoly(3-alkoxythiophene) (PT) with varying ratios of triethylamine and 1-methyl imidazole pendant groups and horizontally aligned single walled carbon nanotubes (SWCNT) are utilized in this study for volatile organic compounds (VOCs) classification. PTs with five different ratios of pendant groups are incorporated with SWCNT and are evaluated as chemiresistor arrays for analysis of VOCs such as ethanol, acetone, toluene, chloroform, isoprene and ethylene. Varying PT pendant groups yielded differential SWCNT current responses attributed to their chemical affinities for the VOCs tested. Principal component analysis (PCA) for vapour classification illustrated that the vapour responses are separable, thus, highlighting vapour discrimination ability of SWCNT with controlled ratios of PT pendant groups. The proposed methodology is a facile VOC classification approach for two main reasons; (i) PT could easily modified with various pendants groups containing appropriate chemical moieties for preferential interaction with various VOCs and (ii) increasing the number PTs with appropriate pendant group modifications would provide additional inputs to PCA thereby enabling capturing and assaying of a wide range of VOCs.Article Citation - WoS: 41Citation - Scopus: 44Vapor Phase Solvatochromic Responses of Polydiacetylene Embedded Matrix Polymers(Royal Society of Chemistry, 2017) Tu, Meng-Che; Cheema, Jamal Ahmed; Yıldız, Ümit Hakan; Palaniappan, Alagappan; Liedberg, BoThe solvatochromic response of polydiacetylene (PDA) in the vapor phase is enabled upon incorporation with matrix polymers such as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyacrylic acid (PAA), and poly-4-vinylpyridine (P4VP). The matrix polymers provide a soft/gel-like framework for accommodating photopolymerized PDA, while facilitating its conformational alternations upon interaction with preconcentrated volatile organic compounds (VOCs). The matrix polymers enabled the differentiation of VOCs owing to their varying morphology, chemical affinity and solubility in VOCs. The ratios between PDA and the matrix polymers are optimized according to the obtained solvatochromic responses evaluated in varying temperature, humidity and storage conditions. As a proof of concept, a finger-print array for differentiation of 7 VOCs is demonstrated using matrix polymer-embedded PDA. The obtained results indicate that the response time and sensitivity of the proposed methodology supersedes previous reports on solvatochromic VOC assays. Furthermore, the proposed methodology would enable differentiation of a wide range of VOCs upon incorporation of additional matrix polymers with varying sorption properties.