Dr. Marleen Kamperman is an invited speaker in the 2nd International Conference on Biological and Biomimetic Adhesives, in Istanbul, Turkey with title of her talk "Physical and Chemical Approaches to Bioinspired Adhesive Design". Abstract for the talk can be found below.
"Physical and Chemical Approaches to Bioinspired Adhesive Design"
Nature has developed elegant and economical strategies to produce multi-functional and adaptive materials. Drawing inspiration from a diverse set of natural examples our main aim is to develop new polymeric materials with altered morphologies and mechanical properties. In this talk I will discuss two projects:
1) Reversible nanostructured adhesive surfaces
Biological attachment systems, found in e.g. geckos, flies and grasshoppers, differ dramatically from conventional adhesives. Unlike many conventional adhesives that can only be used once on clean, smooth surfaces, and attach accidentally to inappropriate surfaces, natural so-called "dry adhesives" are reversible, durable, controllable and self-cleaning. The key strategy in dry adhesives is the incorporation of patterns, i.e. fibrillar surfaces or complex subsurface structures. We developed a nanofabrication processes based on colloidal self-assembly, which allows the fabrication of elastomers patterned with nanodimples. Compared to smooth interfaces, adhesion of these nanopatterned surfaces was enhanced, and the pull-off force scaled inversely with dimple amplitude. All nanopatterned surfaces showed a significant decrease in friction.
2) Catechol containing polymers
3, 4-Dihydroxyphenylalanine (DOPA) is known to play an important role in strong and enduring attachment of biological systems under wet conditions, such as mussels and sandcastle worms. Much effort has been made to mimic the adhesion properties by synthesizing polymers containing catechol groups. A common synthesis method is the radical polymerization of vinyl monomers bearing un-protected catechol groups. Catechol groups are known to be radical scavengers. This scavenging ability may trigger the catechol to react with the propagating radicals and consequently result in the formation of branched polymer chains. However, in previous work, the structure of the obtained polymer is always presented as linear polymer chain and little discussion was presented on the possible side reactions. In this work, we synthesized copolymers of dopamine methacrylamide(DMA) and 2-methoxyethyl acrylate (MEA) using free radical polymerization with different comonomer ratios. The polymers are characterized using different techniques, including SEC-MALLS, 1H NMR, DSC and DMA. It was found that the degree of branching indeed increases with increasing DMA content in the polymer, which explains the poor solubility of homopolymer poly(dopamine methacrylamide). The adhesion performance of these polymers was evaluated under dry and wet conditions.