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|Title:||Surface Patterning, Electronic Device Fabrication And, Three-Dimensional Self-Assembly Using Polydimethylsiloxane|
|Author(s):||Motala, Michael Jonathan|
|Doctoral Committee Chair(s):||Nuzzo, Ralph G.|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||A masterless decal transfer lithography technique is herein described for pattering with polydimethylsiloxane (PDMS). This procedure uses a novel ultraviolet zone (UVO) exposure mask, which allows for the photopatterning of UVO modifications of PDMS surfaces. This modification enables the direct photoinitiated patterning of discrete PDMS patterns without the use of a master. The UVO activated PDMS regions are chemically bonded to oxide bearing surfaces with a greater strength than the modulus of the PDMS and mechanically tear into the bulk, generating a surface with triangular relief features. The capabilities and limitations of this technique are investigated. Applications utilizing this technique are subsequently explored and prove to can be useful for generating cone structures to direct neuronal cell growth as well as for generating phase shifting masks with triangular profiles.
Particular emphasis within this thesis is also placed on microelectronics. Soft lithographic approaches were developed to print microstructured semiconductor structures onto flexible substrates in an effort to use discrete semiconductor elements to overcome many current limitations of polymer based flexible electronics. This printing-based approach was further developed and optimized for subretinal implants as well as for micro solar cell applications. These devices not only utilize PDMS as a transferring tool but also embody novel etching strategies developed for micro semiconductor-based devices for mechanically flexible applications.
Further interest presented within deals with manipulating PDMS to fold. This work used light to "program" a flat two-dimensional material so that stain is incorporated within the material. The folding was made possible by swelling the PDMS within an organic solvent. The programmed regions resist the swelling and drive folding in a controlled manor.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.
|Date Available in IDEALS:||2014-12-17|