Integration of Electrospun Materials in Microelectronic and Biomedical Applications
This thesis demonstrates the use of electrospinning and the novel properties of electrospun
materials in two fields.
The microelectronics industry has identified thermal interface materials as one of the
major bottlenecks hindering further integration at packaging level. New concepts based
on metal-polymer composite architectures are needed to fulfill current and future thermal
and thermomechanical requirements on thermal interface materials at maintained cost
efficiency. In this thesis, an interpenetrating phase polymer-metal composite for thermal
interface material applications has been developed and characterized. Both fabrication
and metrology equipment has been developed for the purpose at hand. The composite is
based on a porous electrospun polymer carrier infiltrated with a high thermal conductivity
metal phase. The two phases form two fully interpenetrating networks in the composite.
Efficient heat transfer is achieved through the continuous metal phase, while the polymeric
phase defines geometry and phase composition. The devised composite architecture is believed
to be a step towards meeting current and future demands on thermal performance
and thermomechanical reliability in microelectronic products.
Furthermore, the thesis presents initial results of human embryonic stem cell proliferation
and neural differentiation in co-culture with electrospun scaffolds, of interest
in future regenerative medicine based on stem cells. Results indicate that physical cues
emanating from cell-scaffold interactions affect cells towards a neuronal fate during differentiation,
a phenomenon consistent with reports in literature on physical cues influencing
stem cell fate. To allow for deeper analysis on cell-scaffold interactions of the
type described above, a microfabricated platform was developed for the purpose. A novel
method for direct photolithographic micropatterning of electrospun polyurethane fibrous
films over large surfaces has been devised. The method allows for assembly of complex
electrospun microstructures on single substrates via a multilayer approach involving multiple
photolithographic exposures, analogous to conventional photolithography in microfabrication
of solid state devices. Indeed, this technique can find application in a variety of
applications where it is beneficial to integrate micropatterned electrospun structures into
microfabricated devices, in particular within biomedical engineering applications.
thermal interface material
Luftbryggan (A810/A811), Kemivägen 9, Chalmers tekniska högskola
Opponent: Dr. Torbjörn M.J. Nilsson, SAAB Microwave Systems AB, Gothenburg, Sweden and Dr. Nina Hellström, University of Gothenburg, Sweden