Chemistry Reference
In-Depth Information
Chart 10.3 Peptidomimetic b-sheet modules with varying numbers of H bonding sites.
polymers having folded nanostructures through programming strong and sacrificial
molecular forces.
10.3.3. 3-D Network Polymers Containing Biomimetic Reversibly
Unfolding Crosslinkers for Advanced Mechanical Properties
Following these basic studies, we applied the modular design concept to bulk
polymer design to enhance its mechanical properties. In our previous studies we syn-
thesized linear PUs and polyesters containing these modules (Guan et al. 2004;
Roland and Guan 2004). Bulk mechanical tests demonstrated that the modular poly-
mers have significantly enhanced mechanical properties. Whereas these systems
demonstrate our initial biomimetic concept, the linear architecture and the lack of
chain orientation may prevent them from manifesting the maximum biomimetic
effects. One important design feature of natural modular polymers is their high
order organization and chain orientation. For example, in collagen (Buehler 2006)
and muscle fibers (McNally et al. 2006), the proteins are oriented uniaxially along
the fiber axis, which ensures cooperative actions of the modules to achieve high
mechanical strength. For practical reasons, this is very difficult to achieve in linear
synthetic polymers. In addition, for the linear polymer system every repeat unit
