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Impact of cellulose fiber organization and novel fiber assembly techniques

Impact of cellulose fiber organization and novel fiber assembly techniques. Jeffrey M. Catchmark Department of Engineering Science and Mechanics Department of Agricultural and Biological Engineering School of Forest Resources Vivek Verma Department of Engineering Science and Mechanics

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Impact of cellulose fiber organization and novel fiber assembly techniques

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  1. Impact of cellulose fiber organization and novel fiber assembly techniques Jeffrey M. Catchmark Department of Engineering Science and Mechanics Department of Agricultural and Biological Engineering School of Forest Resources Vivek Verma Department of Engineering Science and Mechanics Nicole R. Brown School of Forest Resources William O. HancockBioengineering International Conference on Nanotechnology for the Forest Products Industry June 13-15, 2007 Center for NanoCellulosics

  2. Background and motivation for studying cellulose assembly. Impact of mechanical percolation on cellulose nanofiber composite materials. Finite element modeling of idealized cellulose nanofiber architectures. Cellulose nanofiber assembly approach using a system of biomolecular motors and microtubule templates. Summary Overview Center for NanoCellulosics

  3. Cellulose: One of nature’s best materials J.F.V. Vincent, U.G.K. Wegst / Arthropod Structure & Development 33 (2004) 187–199 Center for NanoCellulosics

  4. ~28nm Wood is an exceptional organized nanocomposite • Wood has exceptional mechanical properties not only because of the high modulus of cellulose but also due to the way cellulose is organized with hemicelluloses and lignin in the cell wall. Cellulose nanofiber bundles 6 Assembly proteins (rosette) which produces cellulose nanofibers www.ita.doc.gov/td/forestprod/ jupiter.phys.ttu.edu/corner/1999/dec99.pdf Candace Haigler and Larry Blanton, Cellulose: You're surrounded by it, but did you know it was there? Center for NanoCellulosics

  5. Examples of other natural nanocomposites Many hard biological tissues, such as tooth (a), vertebral bone (b), or shells (c) are made of nanocomposites with hard mineral platelets in a soft (protein) matrix. (From : Huajian Gao, et. al., PNAS, May 13, 2003, vol. 100, no. 10, 5597–5600.) J.F.V. Vincent, U.G.K. Wegst / Arthropod Structure & Development 33 (2004) 187–199. Center for NanoCellulosics

  6. Examples of other natural nanocomposites Scanning electron microscope image of the structure of cuttlefish bone. [Taken from: S. Kannan a, J.H.G. Rocha b, S. Agathopoulos c, J.M.F. Ferreira, “Fluorine-substituted hydroxyapatite scaffolds hydrothermally grown from aragonitic cuttlefish bones”Acta Biomaterialia 3 (2007) 243–249.] J.F.V. Vincent, U.G.K. Wegst / Arthropod Structure & Development 33 (2004) 187–199. Center for NanoCellulosics

  7. Motivation for studying cellulose assembly • Lignocellulose is a major materials industry • Wood, wood fiber composites and paper represent a $250 billion dollar per year industry. • Reduction in the use of fiber could have a major impact. • Consider one grand challenge: Reduce fiber content and thus weight of paper by 50% without impacting its mechanical properties: • Save ~2 billion trees. • Reduce water and chemical consumption by ~50%. • Save ~250 billion gallons of water per year • Save >1.2 quads of energy in U.S.(~8% of all energy used in manufacturing in the U.S., and ~1.2% of the total energy used). Center for NanoCellulosics

  8. Mechanical percolation • Substantial improvements in the mechanical properties of fiber materials (ex: elastic and shear modulus) are achieved when mechanical percolation is reached in fiber composites. Percolation:The formation of connected particles or fibers which span the length of the material. Non-percolated system Percolated system Center for NanoCellulosics

  9. Examples of mechanically percolated materials Enamel, bone, nacre Paper Cuttlefish bone Plant cell wall Center for NanoCellulosics

  10. Finite element mechanical analysis of composites containing nanodimensional cellulose fiber • Cellulose nanofiber dimensions: 10-20nm diameter - 0.5-5 microns length • Ecellulose = 150GPa • Ematrix = 0.5MPa • Fiber distribution: random. (V. Favier, et. al., Polymer Engineering and Science, Vol. 37, No. 10, 1997). Center for NanoCellulosics

  11. Impact of percolation on modulus Percolation threshold Log plot of the measured and calculated shear modulus a function of cellulose fiber volume around the percolation threshold (from V. Favier, et. al., Polymer Engineering and Science, Vol. 37, No. 10, 1997). Center for NanoCellulosics

  12. Impact of percolation on modulus No control over the relationship between fiber organization and percolation threshold Log plot of the measured and calculated shear modulus a function of cellulose fiber volume around the percolation threshold (from V. Favier, et. al., Polymer Engineering and Science, Vol. 37, No. 10, 1997). Center for NanoCellulosics

  13. Strategy for improved cellulosic materials • Engineer fiber organization in cellulose fiber composites to achieve mechanical percolation at lower fiber volumes. • Produce mechanically similar or improved cellulosic materials using less fiber. Center for NanoCellulosics

  14. Finite element modeling of cellulose fiber materials Organized with particles Random with particles Random fiber network Organized fiber network Eeff = 2,790 MPa Eeff = 37 MPa Eeff = 5,460 MPa Eeff = 35 MPa All composites contain 144 cellulose nanowhiskers measuring ~2.8 microns by 80 nanometers. Cellulose connections are assumed to be rigid. Cellulose volume – 14.7% All composites assume E=150GPa for the cellulose and E=0.5MPa for the matrix (after previous studied by Favier, et. al.) Organized composite design assumes E=23GPa for the clay microparticels and E=1GPa for the organic linkers. Model space measures 14.8m14.8m. Center for NanoCellulosics

  15. Impact of particle and linker on material modulus Cellulose (150GPa) Clay (Kaolinite, 23GPa) Organic linker (1GPa) 25nm coating on clay particle Linker modulus very important to final modulus of material Center for NanoCellulosics

  16. Finite element modeling of cellulose fiber materials Eeff = 5,460 MPa Eeff = 7,630 MPa Contour plot of displacement Contour plot of displacement All composites contain 144 cellulose nanowhiskers measuring ~2.8 microns by 80 nanometers. Cellulose connections are assumed to be rigid. Cellulose volume – 14.7% All composites assume E=150GPa for the cellulose and E=0.5MPa for the matrix (after previous studied by Favier, et. al.) Model space measures 14.8m14.8m. Center for NanoCellulosics

  17. Finite element modeling of cellulose fiber materials Eeff = 5,460 MPa Eeff = 7,630 MPa Contour plot of displacement Contour plot of displacement All composites contain 144 cellulose nanowhiskers measuring ~2.8 microns by 80 nanometers. Cellulose connections are assumed to be rigid. Cellulose volume – 14.7% All composites assume E=150GPa for the cellulose and E=0.5MPa for the matrix (after previous studied by Favier, et. al.) Model space measures 14.8m14.8m. Fiber organization resulting in mechanical percolation at lower fiber volumes has the potential for improving the mechanical properties of cellulosic materials. Center for NanoCellulosics

  18. Synthesis approach • System of biomolcular motors and microtubule templates: • Diverse network geometries possible. • 2D surface geometry which can be modeled using finite element analysis. Center for NanoCellulosics

  19. System of biomolecular motors and microtubule templates • Biomotors • Transport intercellular cargo on microtubules. • Chemically powered locally by hydrolysis of adenosine triphosphate (ATP). • Microtubules • Cylindrical polymers which form dynamically inside cells to enable transport. • Biomotors ‘walk’ uni-directionally on microtubules. • System overcomes random Brownian motion at this scale. Newt lung cell Centrosome Cooper, 2nd ed. Center for NanoCellulosics

  20. System of biomolecular motors and microtubule templates • Biomotors and microtubules are proteins. • Many families of biomotor proteins including the kinesin, dynein and myosin. • Microtubules polymerize inside cells via the ordered assembly of  and -tubulin proteins, which are linked with GTP (guanosine tri-phosphate). • Kinesin biomotor head domains connect to the  tubulin subunits. 25 nm Plus end 8 nm 7 nm Kozielski et al. Nogales et al. Cooper, 2nd ed. Center for NanoCellulosics

  21. Microtubules and biomotors: the ‘nanoarchitects’ of the plant cell wall • Microtubule formation controls the orientation of cellulose fibrils in the plant cell wall. Cellulose producing enzyme rosettes glide between membrane bound microtubules creating aligned fibrils. Image by Prof. Malcom Brown, http://www.botany.utexas.edu/facstaff/facpages/mbrown/newstat/stat38.htm Alexander R. Paredez, Christopher R. Somerville, David W. Ehrhardt, Science, Vol. 312, 1491, 2006. Center for NanoCellulosics

  22. - End + End - End + End Glass Substrate In-vitro use of biomotors and microtubules Glass Substrate Microtubule Glass Substrate Direction of motion Casein Cargo Kinesin Center for NanoCellulosics

  23. Self-organizing microtubules: 2D templates for cellulose nanofiber assembly Multi-head motor assembly containing 4 kinesin linking 2 microtubules. Aster formation at different motor assembly concentrations: a) 25g/ml, b) 37.5g/ml, c) 50 g/ml and d) 15 g/ml. F. J. Ne´de´lec, T. Surrey, A. C. Maggs & S. Leibler, NATURE, VOL 389, 18, pp. 305-308, 1997 Center for NanoCellulosics

  24. Building motor complexes Streptavidin binds to 4 Biotin Biotinylate motor end group Image taken from: http://www.arrayit.com/Products/ Substrates/SuperStreptavidin/superstreptavidin.html Center for NanoCellulosics

  25. Polymerization of Microtubule Asters • Polymerization of asters to form microtubule templates with varying degrees of percolation. • Microtubule Aster seeds were formed in solution then immobilized on glass surface • Immobilized microtubule asters were polymerized using tubulin under physiological conditions • During polymerization asters grow in length and get interconnected t = 130 min t = 10 min t = 40 min Center for NanoCellulosics

  26. Degree of interconnectivity in microtubule templates • The connectivity of microtubule asters was measured as a function of time. • The percent connectivity was calculated as the number of asters connected to at least one other aster divided by the total number of asters observed. • All asters are interconnected forming a fully percolated network at ~130 minutes of microtubule polymerization time. Center for NanoCellulosics

  27. Linking biomotors to nanofibers • We have implemented a biotinylation scheme as a means of linking biomotors to cellulose nanofibers. • Biotinylated fibers can be linked to biotinylated kinesin biomotors via a neutravidin protein. • Once a fiber assembly is formed, the microtubules can be depolymerized to remove the template, if desired. Cellulose nanofiber Biotin Streptavidin Biotin Biotinylated microtubule Biotinylation performed using NHS-dPEG™12 Biotin (Quanta Biodesign) Interconnected asters Center for NanoCellulosics

  28. Microtubule on cellulose Control 1: No cellulose Control 2: No neutravidin Control experiment • Confirming that biotinylated microtubules bind only to cellulose • Biotinylated cellulose immobilized on glass followed by neutravidin and biotinylated microtubules: Microtubules bound on surface • Control 1: No cellulose lead to no microtubule binding on surface • Control 2: Neutravidin absence leads to no microtubule binding to cellulose Center for NanoCellulosics

  29. Linking cellulose to microtubules • Assembly of cellulose nanowhiskers over immobilized biotinylated microtubules. Alexa fluor labeled cellulose viewed under Alexa fluor emission filter (647nm) Rhodamine labeled microtubules viewed under Rhodamine emission filter (588nm) Scale bar 20m • Biotinylated microtubules were immobilized on APTES coated glass. • Biotinylated cellulose was bound to the microtubules via biotin- neutravidin link Center for NanoCellulosics

  30. Linking cellulose to microtubules • Continue with microtubule aster templates and percolated fiber networks formed using functional clay microparticles. Alexa fluor labeled cellulose viewed under Alexa fluor emission filter Interconnected asters Finite element model Center for NanoCellulosics

  31. Potential implications for cellulose based materials Organized nanocellulose (theoretical): Eeff (compressive) = 7.6 GPa Fiber volume – 14.7% Paper: Eeff = 4-15 GPa Cellulose fiber volume: ~66% Center for NanoCellulosics

  32. Other approaches: “Bucky Paper” Carbon Nanotube “Bucky paper” Image taken from Carbon Nanotechnologies Incorporated at http://www.cnanotech.com/pages/resources_and_news/gallery/3-2_buckytube_gallery.html Center for NanoCellulosics

  33. Other approaches: “Bucky Paper” Carbon Nanotube “Bucky paper” A little cost prohibitive: >$1,000/sheet Center for NanoCellulosics

  34. Summary • Real need for improved cellulosic materials which incorporate less fiber while maintaining same or superior physical properties. • Organization of cellulose fiber may provide a path toward substantial improvements in the mechanical properties of cellulosic materials and/or substantial reductions in the amount of fiber consumed. • We have demonstrated the ability to produce organized microtubule templates with controllable degrees of mechanical percolation. • We have attached cellulose to the microtubules using a biotin-streptavidin linker. • We are working toward making cellulose composites using these templates and testing their mechanical properties. Center for NanoCellulosics

  35. Acknowledgements • Collaborators: • Prof. Nicole Brown, School of Forest Resources • Prof. William Hancock, Bioengineering • Student: • Vivek Verma, Ph.D. Student, Engineering Science and Mechanics Center for NanoCellulosics

  36. Acknowledgements • National Science Foundation Materials Research Science and Engineering Center (NSF MRSEC) Center for Nanoscale Science. • Center for NanoCellulosics • Ben Franklin Technology Partners of Central and Northern Pennsylvania Center for NanoCellulosics

  37. Thank you! Center for NanoCellulosics

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