Inside Cover, Volume 49, Issue 18


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The figure shows the ideal micromorphology of polyisobutylene (PIB)-based polyurethanes extended with a conventional chain extender (CE) plus a H-bond accepting chain extender (HACE) in the relaxed and stressed states, as presented by Jungmee Kang, Gabor Erdodi, and Joseph P. Kennedy on page 3891. The hard segments present novel morphologies in which conventional CE + diisocyanate (DI) units (blue in the magnified images) are linked to flexible HACEs (green in the magnified images) by covalent and H-bonds (black in the magnified images). The H-bonds of HACEs reinforce the hard segments in the relaxed state, and mediate their deformation under stress.