Porfrin İnce Filmlerin Organik Buhar ile Etkileşim Mekanizmasının Belirlenmesi

Bu çalışmada Langmuir-Schaefer (LS) ince flm üretim tekniği ile 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) porfrin moleküllü ve poly(methyl methacrylate) (PMMA)molekülü kullanılarak çeşitli tabaka sayılarında ince flmler üretildi. Üretilen ince flmlerdeki duyarlı bölgeyi EHOmolekülü oluştururken, PMMA tabakası bir çeşit bariyer olarak kullanıldı. PMMA molekülü polimer yapısındandolayı ince flm olarak transfer edildiğinde birbirine çok yakın bir düzende flm oluşturmaktadır. Dolayısıyla PMMAtabakasının gaz moleküllerinin EHO tabakalarına ulaşmasını engelleyen bir bariyer özelliği göstermesi beklenir.Beklenen bu bariyer etkisini incelemek amacıyla asetik asit buharı kullanılarak ince flm buhar etkileşimleri UVgörünür spektroskopisiyle kaydedildi. EHO ince flmler çok tabakalı üretilerek PMMA tabakasının konumunabağlı olarak sensör tepkileri ölçüldü. Bu sayede ince flm ile gaz molekülleri arasında gerçekleştiği düşünülenfarklı etkileşim aşamaları aydınlatılmaya çalışıldı. PMMA tabakasının farklı konumlarının tepki süresini, hızınıve şiddetini etkilediği görüldü. Teorik olarak varsayıldığı gibi gaz moleküllerinin öncelikle ince flm yüzeyi ileetkileştikleri daha sonra flmin içerisine girerek difüzyon etkileşiminin gerçekleştiği deneysel sonuçlar ile kanıtlandı

Anahtar Kelimeler:

Langmuir-Schaefer, organik sensör, porfrin, pmma

Determination of Interaction Mechanism between Porphyrin Thin Film and Organic Vapor

Langmuir-Schaefer (LS) flms of a free base porphyrin 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) are used in conjunction with a poly(methyl methacrylate) PMMA moleculedeposited as a various layer confguration thin flms. EHO is the active sensing layer and PMMA is a barrier layerfor gas molecules. PMMA molecules stick each other when they transferred on a solid substrate so they can stopvapor molecules before they reach to EHO layers. In order to investigate the gas sensing behaviors acetic acid waschosen for analyte vapor and UV-visible spectrometer was used for sensing system. The layer order of multilayeredLS flms was varied in order to investigate the sensing characteristics and vapor dynamics. It was observed that theplace of PMMA layer effects the response time, speed and intensity. As it is expected from the theoretical studies,the interaction between thin flm and vapor molecules starts from the surface of thin flm and then vapor moleculesstarts to penetrate into flm structure. The experimental results obtained from this study prove this dynamic diffusioneffect between thin flm and vapor molecules. Thus the interaction kinetics between thin flm molecules and vapormolecules were demonstrated using the barrier layer affect.

Keywords:

Langmuir-Schaefer, organic sensor, porphyrin,

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