A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Characterization of Photocleavable Block Copolymer Ultra-Thin Films
Block copolymers have been widely studied in recent years because of their ability to form defined nanostructures with different morphologies and adjustable periodicity. This ability is based on the fact that covalently linked polymer blocks are arranged in well-ordered domains due to both positive enthalpy of mixing and small entropy of mixing. This process is called microphase separation and the molecular size of the individual polymer chains determines their separation distance. In addition, macrophase separation can be avoided, leading to thermodynamically stable nanostructured microdomains. The investigation of highly-ordered thin films is one of the outstanding fields of research in the context of block copolymers since they enable a versatile self-assembled morphology in the range of 5-50 nm by means of a “bottom-up” approach. They promise applications such as polymer membranes or templates for nanostructured materials. Among the block copolymer structures, vertical cylinders have received great attention because of their ability to produce highly-ordered nanopores. Nanopores can be formed from a thin block copolymer film by removing one block by selective etching or by dissolving a polymer block. In this study, polystyrene-block-poly(ethylene oxide) diblock copolymer is used with ortho-nitrobenzyl ester (ONB) as a photocleavable block linker (PS-hν-PEO). The pore material PEO is washed out by a suitable solvent after the two blocks are photocleaved applying mild UV radiation. This results in an arrangement of nanopores which are decorated with functional groups, leading to materials for adsorption or filtration purposes. In the first step of the work, the efficiency of the photocleavage was investigated in solution by FCS measurements in order to determine the exposure time with UV at 365 nm for a quantitative cleavage of the two polymer blocks. In the following experiments ultra-thin polymer films are prepared on top of a silicon substrate and the desired arrangement of the films is then generated by ...
Characterization of Photocleavable Block Copolymer Ultra-Thin Films
Block copolymers have been widely studied in recent years because of their ability to form defined nanostructures with different morphologies and adjustable periodicity. This ability is based on the fact that covalently linked polymer blocks are arranged in well-ordered domains due to both positive enthalpy of mixing and small entropy of mixing. This process is called microphase separation and the molecular size of the individual polymer chains determines their separation distance. In addition, macrophase separation can be avoided, leading to thermodynamically stable nanostructured microdomains. The investigation of highly-ordered thin films is one of the outstanding fields of research in the context of block copolymers since they enable a versatile self-assembled morphology in the range of 5-50 nm by means of a “bottom-up” approach. They promise applications such as polymer membranes or templates for nanostructured materials. Among the block copolymer structures, vertical cylinders have received great attention because of their ability to produce highly-ordered nanopores. Nanopores can be formed from a thin block copolymer film by removing one block by selective etching or by dissolving a polymer block. In this study, polystyrene-block-poly(ethylene oxide) diblock copolymer is used with ortho-nitrobenzyl ester (ONB) as a photocleavable block linker (PS-hν-PEO). The pore material PEO is washed out by a suitable solvent after the two blocks are photocleaved applying mild UV radiation. This results in an arrangement of nanopores which are decorated with functional groups, leading to materials for adsorption or filtration purposes. In the first step of the work, the efficiency of the photocleavage was investigated in solution by FCS measurements in order to determine the exposure time with UV at 365 nm for a quantitative cleavage of the two polymer blocks. In the following experiments ultra-thin polymer films are prepared on top of a silicon substrate and the desired arrangement of the films is then generated by ...
Characterization of Photocleavable Block Copolymer Ultra-Thin Films
Altinpinar, Sedakat (author) / Gutmann, Jochen Stefan
2018-07-19
Theses
Electronic Resource
English
Line Patterns from Cylinder-Forming Photocleavable Block Copolymers
| British Library Online Contents | 2013
Patterning with block copolymer thin films
| British Library Online Contents | 2005
Self-assembly of block copolymer thin films
| British Library Online Contents | 2010
Controlling Orientation and Order in Block Copolymer Thin Films
| British Library Online Contents | 2008
Triggered Cell Release from Materials Using Bioadhesive Photocleavable Linkers
| British Library Online Contents | 2011