Climbing the Ladder to Advanced Rigid Ladder Polymers

Backbone conformation and rigidity are essential factors in determining the properties of macromolecules, as well as the associated supramolecular assemblies and bulk materials. Pursuing a rigid and coplanar molecular conformation often represents one of the primary objectives when designing and synthesizing conjugated polymers for electronic and optical applications. This goal can be achieved by imparting a ladder type constitution in the polymer backbone. This talk includes our efforts on the synthesis of ladder type π-systems fused by various types of bonds, including kinetically formed covalent bonds, thermodynamically formed covalent bonds, coordinate bonds, and hydrogen bonds. The characteristic properties of selected examples of these ladder type π-systems are discussed in comparison with control compounds that are not rigid and coplanar. The fundamental chain rigidity of these polymers are investigated by using advanced neutron scattering techniques. The unique optical, electronic, electrochemical, and mechanical properties of these materials are achieved and tailored in the context of a wide range of applications such as electronics, energy storage, artificial muscles, and stimuli responsive materials.