Development of Ordered Nanocomposites through the use of Block Copolymer Self-Assembly and Additive Manufacturing
Technical Report,01 Feb 2017,31 Jan 2020
UNIVERSITY OF ILLINOIS URBANA United States
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Hierarchically ordered materials have wide-ranging potential benefits through improved mechanical properties and controllable optical, thermal andor electronic properties. To achieve this level of control, a combined bottom-up and top-down approach to materials assembly is needed. Here, we report progress towards this goal by studying the self-assembly, rheology and thermal characteristics of 30 printable block copolymer BCP-containing epoxy inks. We have identified three different BCPs that can self assemble in an epoxyionic liquid system that can be printed using direct ink writing DIW. In this way, the BCPs can direct the bottom-up assembly, while DIW can be used for top-down assembly. Interestingly, we have shown that the SCP-containing inks actually have more favorable rheological properties compared to the base inks. Through this work, we identified transient creep testing as an important rheological characterization method that more directly correlates to the printing process. Lastly, we studied the structural evolution of the BCPs during epoxy curing. We have shown that the samples can be heated to 60 C for several hours without appreciable epoxy crosslinking. While this temperature proved insufficient for significant thermal annealing of the BCP microstructure, it may be helpful to alter the rheology and subsequent printability of the inks. Additionally, we showed that the BCP micelles do not dissociate in the ink during epoxy crosslinking, but the structures do change significantly. Typically, they transition from disordered to higher ordered structures, however these exact ordering mechanisms are still unknown. Overall, this project has greatly increased our knowledge of how these materials behave and sets the stage for further development of hierarchically ordered nanocomposites.
- Manufacturing and Industrial Engineering and Control of Production Systems