- Research Statement:
- Professor Lewis’ research focuses on the design and assembly of soft functional materials. Her group’s efforts are divided into three intertwining thrusts: (1) design and characterization of complex fluids, (2) guided fluidic assembly of colloidal systems, and (3) direct-write assembly of planar and three-dimensional architectures.
Lewis’ first principal achievement is her pioneering work on the direct-write assembly of soft functional materials. Specifically, she and her research group have designed several novel inks for patterning three-dimensional materials at the microscale. Her first papers in this area appeared in Langmuir (2002) and Advanced Materials (2002) and focused on the use of concentrated colloidal gels as inks for direct writing of 3D periodic lattices. This effort was cited as one of the top 7 discoveries in materials chemistry by C&E News in their year-in-review edition. Building on this general approach, she and her collaborators have created ferroelectric (PZT-polymer) composites, hydroxyapatite scaffolds for bone tissue engineering, and interpenetrating alumina/Al composites for structural applications. Recently, she has greatly extended this effort through the design of concentrated silver nanoparticle inks, which enable the omnidirectional printing of flexible, stretchable and spanning microelectrodes for electronic and optoelectronic devices (Science, 2009; Proc. Nat. Acad. Sci., 2009). In addition to printing out-of-plane architectures, she has also recently advanced a new concept for fabricating complex 3D architectures, known as printed origami (Advanced Materials, 2010). In this approach, a new class of colloidal inks have been developed that are capable of printing of planar scaffolds that can be subsequently folded using a wet-folding origami technique. By integrating these two approaches, 3D structures are created that could simply not be fabricated by other means.
Importantly, Lewis’ work in direct-write assembly of soft functional materials extends far beyond colloidal-based systems. As one example, she has designed fugitive organic inks for patterning 3D microfluidic devices (Nature Materials, 2003; Advanced Materials, 2005), self-healing polymeric “skin” with embedded microvascular networks (Nature Materials, 2007; Advanced Materials, 2009), and biomimetic microvascular networks (Soft Matter, 2010). A patent will soon be awarded on this approach. In addition, the collaborative effort on self-healing polymeric “skin” received a SciAm50 Award from Scientific American.
Lewis also pioneered the use of concentrated polyelectrolyte complexes as novel inks for patterning 3D microperiodic structures (Nature, 2004). For this ink design, she drew inspiration from nature in the form of spider silk and web spinning. A patent was issued on this discovery entitled “Directed Assembly of Three-Dimensional Structures with Micron-Scale Features," US Patent# 7,141,617. She also demonstrated that these polyelectrolyte scaffolds could be used as templates for 3D photonic crystals (Advanced Materials, 2006; 2007) and biomimetic mineralization (Soft Matter, 2007). This research then led to the collaborative development of silk fibroin inks for direct-write assembly of 1D polymer waveguides (Advanced Materials, 2009) and 3D tissue engineering scaffolds (Advanced Functional Materials, 2008). Very recently, she has created a new class of hydrogel-based inks for patterning 3D micro-periodic scaffolds for robust cell cultures (Advanced Materials, 2008). She and her collaborators are now investigating this novel platform for culturing human embryonic stem cells (hESCs). Finally, she and her team have created concentrated sol-gel inks for printing 3D photonic crystals (Advanced Materials, 2007) and transparent conducting oxide microelectrodes for printed electronics (Chemical Communications, 2010).
Collectively, her research on direct-write assembly of soft functional materials has led to more than 40 peer-reviewed journal papers, 9 invited review articles and book chapters, 3 patents issued (covering 3D printed structures from colloidal, polyelectrolyte, and fugitive organic inks) and 2 patents filed (covering 3D printed structures from conductive nanoparticle and sol-gel inks). Her research in this area has been featured in 10 cover articles, including those appearing in PNAS (1), Advanced Materials (4), Advanced Functional Materials (1), Langmuir (1), Soft Matter (2), and Materials Today (1). Her direct-writing research has also garnered considerable attention in scientific journals and the popular press with feature stories appearing in Science, Nature Materials, Chemical and Engineering News, Scientific American, Technology Review, and The Economist to name a few. Her work in this area is being transitioned to the commercial sector through funded efforts with two well-established companies with interests in colloidal and fugitive ink writing, respectively.
Lewis’ second principal achievement is her seminal work on colloidal stabilization and assembly. Nearly a decade ago, she discovered a new colloidal stabilization mechanism, known as nanoparticle haloing (Proc. Nat. Acad. Sci., 2001; cover article), which arises in binary mixtures composed of negligibly charged microspheres and highly charged nanoparticles. She then used these novel mixtures to assemble colloidal crystals via an epitaxial templating approach (Langmuir, 2004); and, more recently, to create patterned colloidal films via evaporative lithographic patterning of colloidal films (Physical Review Letters, 2007; Langmuir, 2008; Phil. Trans. A., 2009; Editor’s Choice, Science Magazine, 2009).
Under support from W.R. Grace (2001-04), she led a project that provided new insight into the mechanisms by which comb polymer dispersants, known as superplasticizers, give rise to improved cement paste formulations and rheology. She and her PhD student, Glen Kirby, received the Brunauer Award from the American Ceramic Society, Division of Cement Materials in 2003 in recognition of this work. The impact of this discovery is in fact far broader, since comb polymer dispersants have proven to be highly effective in stabilizing a wide range of colloidal suspensions (J. Am. Ceram. Soc., 2004; Langmuir, 2006; 2009). A patent was issued on this discovery entitled “Controlled Dispersion of Colloidal Suspension by Comb Polymers”, US Patent #7,053,125.
Collectively, her research on colloidal stabilization and assembly has led to nearly 30 peer-reviewed journal papers and 4 invited review articles. Of these, her work has been featured in 5 cover articles, including those appearing in PNAS (1), Advanced Materials (1), Langmuir (1), and Journal of the American Ceramic Society (2). This research has also garnered considerable attention in scientific journals and the popular press with feature stories appearing in Science, Chemical and Engineering News, and Photonics Spectra.
- Research Interests:
- Direct-write assembly, complex fluids, microfluidics, photonics, colloids, rheology
- Materials Assembly, Complex Fluids, and Mesoscale Fabrication
- For more information:
- Lewis Group website
Honors, Recognition, and Outstanding Achievements for Teaching:
- Outstanding Advisors List
- Burnett Teaching Award
- Daily Illini’s Incomplete List of Teachers Ranked Excellent by Their Students
Honors, Recognition, and Outstanding Achievements for Research:
- MRS Medal
- Fellow, American Academy of Arts and Sciences
- Fellow, Materials Research Society
- George Weatherly Lecture – Composites at Lake Louise
- Keynote Lecture – Australian Interface and Colloids Science Meeting
- Keynote Lecture – American Chemical Society Colloids Meeting
- Langmuir Lecture Award, American Chemical Society
- MIT DMSE Visiting Committee Member
- Keynote Lecture – International Conference on Ceramic Processing Science
- Penn Engineering Grace Hopper Lecture
- Plenary Talk, Society of Rheology
- Plenary Talk, Composites at Lake Louise
- SciAm50, research on self-healing materials with embedded microvascular networks
- Fellow, American Physical Society
- Meeting Chair, 2007 Spring MRS Meeting
- Plenary Talk, International Conference on Ceramic Processing Science
- Featured Public Lecture, Boulder School for Condensed Matter and Materials Physics
- NSF Advance Lecturer, Case Western Reserve University
- Fellow, American Ceramic Society
- International Editorial Advisory Board Member, Soft Matter
- Hans Thurnauer Professorship
- Research highlighted in Science&Vie as a nanoscience image of the year
- Brunauer Award, American Ceramic Society
- Editorial Advisory Board Member, Langmuir
- External Advisor, Unilever
- Keynote Lecture, Shaping of Advanced Ceramics, Belgium
- Willett Faculty Scholar Award
- Research cited by C&E News as 2002 highlight
- Xerox Award for Faculty Research
- University Scholar Award
- NAE Frontiers of Engineering, Invited Participant
- Allied Signal Foundation Award
- Associate Editor, Journal of the American Ceramic Society
- Xerox Award for Junior Faculty Research
- MRS Travel Award for Young Scientists, International Conf. on Advanced Materials
- Schlumberger Foundation Award
- Arnold O. Beckman Research Award
- NSF Presidential Faculty Fellow Award
- NSF Research Initiation Award