Ilhan A. Aksay, Princeton University
Professor
Princeton, New Jersey
iaksay@Princeton.EDU
Office:
(609) 258-4393
Bio/Research
Materials processing with complex fluids is the central theme of our research activities. Complex fluids such as colloids and/or amphiphilic solutions spontaneously self-assemble to produce ordered nanostructures, an essential step in the design and processing of materials [D.M. Dabbs, I.A. Aksay...
Click to Expand >>
Click to Expand >>
Bio/Research
Materials processing with complex fluids is the central theme of our research activities. Complex fluids such as colloids and/or amphiphilic solutions spontaneously self-assemble to produce ordered nanostructures, an essential step in the design and processing of materials [D.M. Dabbs, I.A. Aksay, Annu. Rev. Phys. Chem. 51 601 (2000)]. Many of our activities draw inspiration from biological systems (see following figure) [R.Z. Wang, Z. Suo, A.G. Evans, N. Yao, I.A. Aksay, J. Mater. Res. 16 2485 (2001)]. Like the biological analogs that provide inspiration, our goal is to shape new systems that are multifunctional, "smart" in their ability to detect and respond to changes in environmental conditions, and capable of self-healing.
Guided self-assembly of nanostructured composites. Although self-assembly provides locally ordered nanostructures similar to those observed in biological systems, global order is not attained due to the statistical nature of the ordering process. We explore the role of electrohydrodynamic effects to guide the global order by a variety of techniques that have derived their fundamental understanding from joint studies with D.A. Saville [W.D. Ristenpart, I.A. Aksay, D.A. Saville, Phys. Rev. Lett. 90 128303 (2003)]. Colloidal patterning through cone-jet printing is one technique that offers the potential to produce patterns at the nanometer scale rapidly and over large areas.
Self-healing materials. Man-made materials lack the ability for self-repair; whereas biologically produced materials sense and repair defects through cellular activities. Concepts generated from model studies provide new approaches for the development of man-made materials with self-repair functions. Our synthetic analogs are built with arrays of microreactors through pixelated structures similar to those used in LCD technology. For instance, when an organic/inorganic hybrid coating is damaged, the damaged region heals spontaneously [N. Yao, A.Y. Ku, H. Nakagawa, T. Lee, D.A. Saville, I.A. Aksay, Chem. Mater. 12 1536 (2000)]. Further, the rate of self-repair is enhanced with the application of weak electrical fields (~102 V/m). In a second example, we partially mimic the process of blood clotting as a process of colloidal aggregation at a defect site. We then make this a permanent protective layer, for instance, through the electrodeposition of a metal binder in the interstitials of the colloidal aggregate. In both approaches the mechanisms are not yet fully understood.
Microsensors and actuators. Our goal is to develop arrays of piezoelectric microcantilevers (e.g., PbO-ZrO2-TiO2 (PZT)) that replicate the process of gathering physical and chemical metrics in vivo. We explore the feasibility of using arrays of nanocomposite microcantilevers [C.R. Martin, I.A. Aksay, J. Phys. Chem. B 107 4261 (2003)] as biosensors that are capable of simultaneously measuring, in real time, multiple biophysical and biochemical properties of fluids in the human body [W.Y. Shih, X. Li, H. Gu, W.-H. Shih, I.A. Aksay, J. Appl. Phys. 89 1497 (2001)]. A nanostructured coating (L3 templated silica) gives enhanced sensitivity due to the presence of features from 5 to 30 nm in size that, in turn, give rise to a large effective surface-area (>1000 m2/g).
Click to Shrink <<
Guided self-assembly of nanostructured composites. Although self-assembly provides locally ordered nanostructures similar to those observed in biological systems, global order is not attained due to the statistical nature of the ordering process. We explore the role of electrohydrodynamic effects to guide the global order by a variety of techniques that have derived their fundamental understanding from joint studies with D.A. Saville [W.D. Ristenpart, I.A. Aksay, D.A. Saville, Phys. Rev. Lett. 90 128303 (2003)]. Colloidal patterning through cone-jet printing is one technique that offers the potential to produce patterns at the nanometer scale rapidly and over large areas.
Self-healing materials. Man-made materials lack the ability for self-repair; whereas biologically produced materials sense and repair defects through cellular activities. Concepts generated from model studies provide new approaches for the development of man-made materials with self-repair functions. Our synthetic analogs are built with arrays of microreactors through pixelated structures similar to those used in LCD technology. For instance, when an organic/inorganic hybrid coating is damaged, the damaged region heals spontaneously [N. Yao, A.Y. Ku, H. Nakagawa, T. Lee, D.A. Saville, I.A. Aksay, Chem. Mater. 12 1536 (2000)]. Further, the rate of self-repair is enhanced with the application of weak electrical fields (~102 V/m). In a second example, we partially mimic the process of blood clotting as a process of colloidal aggregation at a defect site. We then make this a permanent protective layer, for instance, through the electrodeposition of a metal binder in the interstitials of the colloidal aggregate. In both approaches the mechanisms are not yet fully understood.
Microsensors and actuators. Our goal is to develop arrays of piezoelectric microcantilevers (e.g., PbO-ZrO2-TiO2 (PZT)) that replicate the process of gathering physical and chemical metrics in vivo. We explore the feasibility of using arrays of nanocomposite microcantilevers [C.R. Martin, I.A. Aksay, J. Phys. Chem. B 107 4261 (2003)] as biosensors that are capable of simultaneously measuring, in real time, multiple biophysical and biochemical properties of fluids in the human body [W.Y. Shih, X. Li, H. Gu, W.-H. Shih, I.A. Aksay, J. Appl. Phys. 89 1497 (2001)]. A nanostructured coating (L3 templated silica) gives enhanced sensitivity due to the presence of features from 5 to 30 nm in size that, in turn, give rise to a large effective surface-area (>1000 m2/g).
Click to Shrink <<