“Smart” Adhesion: Controlling Polymer Interfaces with PatternsAlfred J. Crosby, University of Massachusetts, DMR-0349078

From nano-imprint lithography to protective foams on the space shuttle, adhesion plays an important role in numerous cutting-edge applications. Nature has shown us through examples like the gecko and lotus leaf that interfacial strength can be enhanced, and more importantly, tuned through the combination of geometric patterns and material properties. We are following these examples and exploring the fundamental relationship between material : pattern : adhesion for synthetic materials. Our initial research on low adhesion, elastomers allowed us to develop scaling relationships linked to material-defined length scales.1 These relationships demonstrate that adhesion can be significantly enhanced (right) as a pattern length scale approaches critical, material-defined limits. We have used these discoveries to control fingering and cavitation processes in soft, viscoelastic polymer coatings (bottom right). By controlling the growth of these dissipative processes, adhesion can be tuned. Recently, we have explored alternatives to the direct assembly of adhesion-controlling patterned surfaces. One example is the use of elastic instabilities, tailored elastic moduli, and photopolymerization to fabricate stable, user-defined patterns that self-assemble (bottom left).2

1 Crosby, A.J., Hageman, M., Duncan, A. submitted to Langmuir, 2005.2 Chan, E.P., Crosby, A.J. submitted to Nature Materials, 2005.

“Smart” Adhesion: Controlling Polymer Interfaces with PatternsAlfred J. Crosby, University of Massachusetts, DMR-0349078

Education Through ResearchThis grant and a Research Experience for Undergraduates (REU) supplement is currently supporting two Ph.D. candidates and three undergraduate researchers (right). This has allowed the creation of a diverse, vibrant research group that truly has fun leading discoveries in polymer science research.

Preparing Researchers Through EducationThis grant has also been used to develop a new course focused on training science-related graduate students in “soft” skills and management strategies. Topics include:

•Leadership•Proposal writing•Group Management•Communication in Diverse Environments•Ethics•Life After Grad School: Academia vs. Industry

In Spring 2005, this course entered its second year. It grew from a total of 16 students (representing 4 departments) in the first year to over 45 students (representing over 8 departments and 2 colleges). Most importantly, this enrollment includes a large number of women and under-represented minorities that traditionally do not learn these skills through the conventional informal processes. The course will be offered this coming Spring with continued expansion, including the parallel teaching of this course at the University of California at Davis.

“This course is amazing. I have learned so much about my career options and how to gain what I want from my academic experience as a Ph.d student more than from any other course.”-- student evaluation