| 학회 | 한국재료학회 |
| 학술대회 | 2010년 가을 (11/11 ~ 11/12, 무주리조트) |
| 권호 | 16권 2호 |
| 발표분야 | D. Health and Biological Materials(생체 및 의용재료) |
| 제목 | NATURE-INSPIRED HYBRID STRUCTURAL MATERIALS |
| 초록 | The structure of materials invariably defines the mechanical behavior. However, in most materials, specific mechanical properties are controlled by structure at widely differing length scales. Nowhere is this more apparent than with biological materials, which are invariably sophisticated composites whose unique combination of mechanical properties derives from an architectural design that spans nanoscale to macroscopic dimensions. Moreover, they are generally able to defeat the “law of mixtures” by devising such hierarchical structures with weak constituents into strong/tough hybrid materials that display superior properties to their individual constituents. Nature has successfully used this approach over billions of years, yet despite intense interest by the scientific community, it has yielded few real technological advances in the design of new structural materials. Studies that “bridge the length scales” have become increasingly popular but are largely based in the area of mechanics rather than mechanistic understanding. Without discovery of mechanisms, new material design is merely empirical. In this presentation we describe attempts to develop a range of bone- and nacre-like structural materials using a new freeze-casting technique, which utilizes the intricate structure of ice to create hybrid materials with complex lamellar and/or mortar and brick structures modeled across several length-scales. Our initial results show ceramic-polymer and ceramic-metal hybrid materials with toughness well in excess of those expected from a rule of mixtures construction. The architecture and properties of the synthetic materials are compared to their natural counterparts in order to identify the mechanisms that control mechanical behavior over multiple dimensions and propose new design concepts to guide the synthesis of hybrid/hierarchical structural materials with unique mechanical responses. Robocasting is a computer guided micro-extrusion process that permits the printing of ceramic scaffolds with very complex geometries. The printing inks can be processed both from ceramic powders or sol-gel precursors. In freeze casting, porous scaffolds are templated by controlling the directional growth of ice crystals on ceramic-based suspensions. The porous structure is modified by changing the composition of the ceramic colloidal suspension, by controlling the freezing conditions and by patterning the cooling surface. In sol-gel templating the porous structures are formed by the controlled crystal growth of volatile inorganic salts inside ceramic sol-gels. This technique creates highly porous interconnected structures. Mechanical response, biological compatibility and specific surface areas are compared in order to evaluate the technological potential of the various structures. Support is provided by the National Institute of Health under grant number NIH/NIDCR 1R01 DE11289 and 1 R01 DE015633 |
| 저자 | Antoni P. Tomsia |
| 소속 | Lawrence Berkeley National Laboratory |
| 키워드 | spans nanoscale; bone; bio-inspired |
