The work reported herein concerns the production and characterisation of ordered microporous and nanoporous polymer films. High speed microphotographic (HSMP) studies of the formation process reveal that near the surface of a suitable polymer solution, vapour condensation produces near monodisperse water droplets which form a close-packed monolayer (or ‘breath figure’. Following solvent evaporation, characterisation of the residual solid form by Atomic Force Microscopy and Scanning Electron Microscopy reveals that its surface has extensive regions of hexagonally close-packed microscopic pores, whose spatial arrangement replicates that of the initial droplet monolayer. Atomic Force Microscopy shows that the surficial pores represent open sections of sub-surficial spheroidal cavities formed by encapsulation of the water droplets within the polymer solution. An interesting feature is the occurrence of nano-scale pores at the film surface and within the walls of the sub-surficial pores. This is the first physical evidence report of such features in porous polymer films produced by a process involving breath-figures. Moreover the work reported herein reveals, for the first time, that the structural template represented by the water droplet array is directly transferred into the resulting solid polymer film and, in doing so, maintains the features present in the water droplet array. This work provides the first direct (i.e. non-circumstantial) association between the droplet template and pore structure in breath figure work. Previous reports of this process have merely been able to report that the pores are not formed in the absence of moisture. The mechanism whereby substantial regions of the water droplet ‘raft’ (or array) are transferred en masse into the rapidly evaporating polymer solution is essentially that envisaged by Srinivasarao <i>et al</i> (2001), and the present work provides the first experimental confirmation of their ideas.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637451 |
| Date | January 2005 |
| Creators | Jones, R. L. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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