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Multi-functionality plays a decisive role in tuning and improving fundamental properties of active molecules, and grafting polymerization/conjugation development imparts properties of active molecules to the backbones. Recently, metal-polyphenol coordination networks have attracted a great deal of attention. A variety of transition metal ions can freely combine with catechol/keto-enol containing polyphenols to form metal-polyphenol networks. Herein, the recently studied conjugated polyphenols were summarized and compared to dopamine-conjugated polymers with evaluation of their properties and gelation behaviors. The biomimetic understanding of bioinspired adhesion, metal ion coordination of hydroxyl groups, and their rearrangement within aglycone could expand the ability for the development of biomimetic, eco-friendly, and biocompatible polymers.

Recently, numerous attempts have been made to engineer micro- and nano-porous surface patterns or to develop convenient preparation methods for the practical applications of self-cleaning surfaces, water-repellent surfaces, novel textures, etc. Herein, we introduce a simple, cheap, and repeatable crystallization-based method to produce porous surface structures, on any surface of already fabricated polymeric materials. Contact of the solvent phase with cooled polymer surfaces enabled the limited dissolution of the surfaces and the subsequent extremely fast melt crystallization of the solvent. After removing the crystals, various micro- and nano-porous patterns were obtained, whose pore sizes ranged over three orders of magnitude. Pore depth was linearly dependent on the dissolution time. Crystal growth was mainly directed normal to the surfaces, but it was also controlled in-plane, resulting in cylindrical or lamellar structures. Superhydrophobic surfaces were successfully prepared on both polystyrene and polycarbonate. This process offers a novel surface engineering tool for a variety of polymer surfaces, whose topology can be conveniently controlled over a wide range by crystal engineering.

Silicone-based polymers have been widely used for many applications, but their extremely low surface energies and the resulting poor adhesion have been the cause for continuous problems. Herein, a novel adhesion improvement technique using an interlocked finger structure is demonstrated, which enables up to 24.8 and 7.3-fold increases in adhesion compared to the untreated and conventional plasma-treated cases, respectively. The interlocked finger structure is fabricated by surface-confined dissolution and subsequent directional melt crystallization of a solvent. After removing the solvent crystals, porous surfaces are prepared from polyurethane, polyvinyl alcohol, and polystyrene, and these are used to fabricate interfaces of interlocked finger structures with polydimethylsiloxane. The improvement in adhesion strength linearly depends on the pore depth of the prepared surfaces. This novel technique of surface adhesion could improve the performance of polymers with intrinsically poor adhesion in future applications.