Development of a Scaleable Breath-figure Type Polymer Thin Film Patterning Process via Controlled Vapour Swelling of Thin Films
File Type:
PDFItem Type:
ThesisDate:
2023Author:
Access:
embargoedAccessEmbargo End Date:
2025-02-01Citation:
Darragh, Philip, Development of a Scaleable Breath-figure Type Polymer Thin Film Patterning Process via Controlled Vapour Swelling of Thin Films, Trinity College Dublin, School of Chemistry, Chemistry, 2023Download Item:
Abstract:
Efficient production of microporous polymeric films can be rapidly synthesised by changing
the thermodynamics of a polymeric solution in a humid atmosphere. This conventional
method, known as ?breath figure? (BF), involves drop casting a volatile polymer solution on
to a flat surface and results in an evaporative cooling effect. Once the temperature of the
polymer solution reaches the dew point, water droplets begin to condense on to the surface
and their morphology dictates the micropore?s density and size that exist within the polymer
film. The BF method has received significant attention in respect to the process creating
homogenous porosity in polymer thin films in less than 5 minutes. However, the
conventional method has its flaws in respect to reproducibility and defects over large surface
areas. Here a new method is outlined using a customised piece of apparatus that can create
various film porosity by precisely controlling and automating all variables that occur within
the BF process, solvent saturation, relative humidity, temperature, and polymer type.
The polymer of interest that has been studied in significant detail is polystyrene (PS), a low cost polymer that has high spin-coating thickness uniformity, process stability and functions
as a dry etch resist. By swelling the PS film of uniform thickness in a favourable solvent, the
viscosity can be decreased creating a viscoelastic mouldable film that can be templated by
water droplets at the temperature dew point. This process can remove the problems with
fluid dynamics, by controlling the swelling of the film through temperature control and the
in-situ swelling can be characterised by reflectometry. This approach can allow us to
understand the role of thermodynamics on water droplet templating and interpret the effects
of polymer swelling on the production of the microporous materials. Using these concepts,
a fast method for producing different sizes of microporous PS resists can be assessed. These
templates can function as pattern-transfer templates for countless lithographic techniques
and methodologies.
Author's Homepage:
https://tcdlocalportal.tcd.ie/pls/EnterApex/f?p=800:71:0::::P71_USERNAME:DARRAGHPDescription:
APPROVED
Author: Darragh, Philip
Advisor:
Morris, MichaelPublisher:
Trinity College Dublin. School of Chemistry. Discipline of ChemistryType of material:
ThesisAvailability:
Full text availableMetadata
Show full item recordLicences: