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Biomimetics Learning from nature Part 9

Tham khảo tài liệu 'biomimetics learning from nature part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 238 Biomimetics Learning from Nature First given the difference between testing methods the reduced Young s modulus above cannot be directly compared with Young s modulus 48.5 GPa of nacre in the recent three-point bend test. Second in addition to ordered layered structure interfacial compatibility of the organic and inorganic components is a key factor. From this aspect only certain types of polymer are effective in dramatically enhancing mechanical properties of such composite films. Thus whether AAER is most suitable or not is still unknown. Third the thicknesses of organic layers and inorganic layers in our nano-laminated films are much thinner than those in nacre. In natural nacres the biopolymer layers are usually 10-50 nm thick providing necessary space for tight folding of polymer chains and certain degree of cross-linking of polymer. In comparison in our laminated structure polymer is confined within the interlayer space of smaller than 2 nm. Thus the degree of cross-linking of AAER with its percentage in total organic content is probably low consistent with the result that no distinction in FTIR spectra and XRD patterns were observed between the as-deposited HMMT film and the heat-treated HMMT film. Meanwhile aragonite layers in nacre are 200-900 nm thick hundreds of times thicker than the clay layers in our film. This may well explain why natural nacre adopts the micro nano composite structure but not the nano nano composites structure. Research on the preparation of micro nano laminated organic-inorganic composites is being conducted by our group. Fourth properties of clay platelets are fairly different with aragonite. Clay platelets are extremely compliant while aragonite is much more rigid. Additionally CaCO3 blocks have nano asperities that are about 30 100 nm in diameter 10 nm in amplitude providing additional friction when one block is sliding on the other. 4.3. Summary The special assembly method hydrothermal-electrophoretic assembly was .