Séminaire avec Colin Bridges, University of California, Santa Barbara
Résumé :
Electroactive carbon based polymers are central to many nascent green technologies including energy efficient lighting, photovoltaics, energy storage, and semiconductors. The unit cell, size, fraction, and orientation of crystallites in polymer electronics can vastly influence the electronic properties. As such, gaining control over both short and long-range molecular ordering is vital for understanding and optimizing how these devices function. Liquid crystalline conjugated polymers are attractive systems for this since they exhibit high fidelity ordering, their structure is in equilibrium, and the molecular alignment is readily propagated from molecular to macroscopic length scales. I will discuss how amphiphilicity between the polymer backbone and side-chain can influence the formation and structure of liquid crystalline mesophases in semiconducting polymers. I will also explore how sidechain design can be leveraged to control unit cell and intermolecular interactions. These molecular features are correlated with macroscopic features such as alignment propagation, and the electronic properties of polymer transistors. These findings are used to establish molecular design rules governing mesoscale properties, and represent a general approach to allow the expression and alignment of lyotropic liquid crystalline mesophases in conjugated polymers
