Functionalizable molecular tubing synthesis combining self-immolative polymers and rotaxanes

Carbon nanotubes are used daily for many applications such as support for automotive parts, water filtration and energy storage, due to their high tensile strength and lightweight nature. However, a limitation lies in their structure since pure carbon does not allow for easy nor high yielding ways to add functional groups in the molecular structure. A variation of organic molecular tubing with modifiable groups can be constructed from synthesizing polyrotaxanes, which are repeating units of interlocked self-immolative polymers (SIPs) and macrocyclic compounds. SIPs are molecules which are specifically end capped for stability until it encounters a specific environmental condition that causes the polymer to spontaneously degrade. Endcaps can be selectively chosen to destabilize under certain stimuli such as enzymes, UV light and chemical analytes allowing for SIP’s to be used in a variety of functions such as drug delivery. Currently, most research focus on linear SIP’s to form spheres encapsulating drug molecules that deliver into cancer cells. Our work introduces a novel benzimidazole-backbone, resulting in a SIP that includes blocky ends which physically locks functionalized macrocycles in place to allow for cross linkage and any post-modifications. Application of a specific stimulus would allow for the inner bulky groups to degrade and ultimately leave a hollow molecular tube with the specific functionalizations desired