Using a breath-figure method to self-organize honeycomb-like polymeric films from dendritic side-chain polymers

In this study, we investigated various generations of waxy dendrons, dendritic side-chain polymers (varying the structure and polarity of the polymer backbone), and physical blends of dendrons with polymers for their ability to form honeycomb-like structures. Each waxy dendron comprises a focal part (possessing many hydrogen bonding sites) and a peripheral part (rich in units that undergo van der Waals interactions). Using a breath-figure process, we readily incorporated high-generation dendrons within polymer matrixes to form porous surfaces. When the high-generation waxy dendrons were grafted onto amino group – functionalized polystyrene or copolymerized with diisocyanates to form polyurethanes, the multiple long alkyl chains behaved as bristles of hydrophobic brooms, due to the presence of strong van der Waals forces. The formation of honeycomb-like patterns in the polymer films resulted from strong hydrogen bonding of the polymers to water droplets on the surfaces of substrates, with subsequent self-organization and phase separation.