Shape-memory nanoparticles from inherently non-spherical polymer colloids
Source abstract
Abstract
Samples of polymeric materials generally have no intrinsic shape; rather their macroscopic form is determined by external forces such as surface tension and memory of shear (for example, during extrusion, moulding or embossing). Hence, in the molten state, the thermodynamically most stable form for polymer (nano)particles is spherical. Here, we present the first example of polymer nanoparticles that have an intrinsic non-spherical shape. We observe the formation of high-aspect-ratio ellipsoidal polymer nanoparticles, of controlled diameter, made from main-chain liquid crystalline polymers using a mini-emulsion technique. The ellipsoidal shape is shown to be an equilibrium (reversible) characteristic and a direct result of the material shape memory when a liquid crystal nanoparticle is in its monodomain form.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Photonic Crystals and Applications · Advanced Materials and Mechanics · Liquid Crystal Research Advancements
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References (22)
Show source-provided references
1. Donald, A. M. & Windle, A. H. Liquid Crystalline Polymers (Cambridge Univ. Press, Cambridge, 1992).
2. Warner, M. & Terentjev, E. M. Liquid Crystal Elastomers (Clarendon, Oxford, 2003).10.1093/oso/9780198527671.001.0001 ↗
3. Finkelmann, H., Nishikawa, E., Pereira, G. G. & Warner, M. A new opto-mechanical effect in solids. Phys. Rev. Lett. 87, 015501 (2001).10.1103/PhysRevLett.87.015501 ↗
4. Küpfer, J. & Finkelmann, H. Liquid-crystal elastomers: influence of the orientational distribution of the crosslinks on the phase behaviour and reorientation processes. Macromol. Chem. Phys. 195, 1353–1367 (1994).10.1002/macp.1994.021950419 ↗
5. Joannopoulos, J. D., Villeneuve, P. R. & Fan, S. Photonic crystals: putting a new twist on light. Nature 386, 143–149 (1997).10.1038/386143a0 ↗
6. Lu, Y., Yin, Y. & Xia, Y. Three-dimensional photonic crystals with non-spherical colloids as building blocks. Adv. Mater. 13, 415–420 (2001).10.1002/1521-4095(200103)13:6<415::AID-ADMA415>3.0.CO;2-O ↗
7. Xia, Y., Gates, B., Yin, Y. & Lu, Y. Monodispersed colloidal spheres: old materials with new applications. Adv. Mater. 12, 693–713 (2000).10.1002/(SICI)1521-4095(200005)12:10<693::AID-ADMA693>3.0.CO;2-J ↗
8. Matijevic, E. Uniform inorganic colloid dispersions. Achievements and challenges. Langmuir 10, 8–16 (1994).10.1021/la00013a003 ↗
9. Morales, M. P., Gonzalez-Carreno, T. & Serna, C. J. The formation of α-Fe2O3 monodispersed particles in solution. J. Mater. Res. 7, 2538–2545 (1992).10.1557/JMR.1992.2538 ↗
10. van Dillen, T., van Blaaderen, A. & Polman, A. Shaping colloidal assemblies. Mater. Today 7, 40–46 (2004).10.1016/S1369-7021(04)00345-1 ↗
11. Jiang, P., Bertone, J. F. & Colvin, V. L. A lost-wax approach to monodisperse colloids and their crystals. Science 291, 453–457 (2001).10.1126/science.291.5503.453 ↗
12. Ho, C. C., Keller, A., Odell, J. A. & Ottewill, R. H. Preparation of monodisperse ellipsoidal polystyrene particles. Colloid Polym. Sci. 271, 469–479 (1993).10.1007/BF00657391 ↗
13. Lu, Y., Yin, Y. & Xia, Y. Preparation and characterization of micrometer-sized 'egg shells'. Adv. Mater. 13, 271–274 (2001).10.1002/1521-4095(200102)13:4<271::AID-ADMA271>3.0.CO;2-T ↗
14. Percec, V. & Kawasumi, M. Liquid-crystalline polyethers based on conformational isomerism. 18. Polyethers based on a combined mesogenic unit containing rigid and flexible groups: 1-(4-hydroxy-4′-biphenyl)-2-(4-hydroxyphenyl)butane. Macromolecules 24, 6318–6324 (1991).10.1021/ma00023a039 ↗
15. Grell, M., Bradley, D. D. C., Inbasekaran, M. & Woo, E. P. A glass-forming conjugated main-chain liquid crystal polymer for polarized electroluminescence applications. Adv. Mater. 9, 798–802 (1997).10.1002/adma.19970091006 ↗
16. Landfester, K. et al. Semiconducting polymer nanospheres in aqueous dispersion prepared by a miniemulsion process. Adv. Mater. 14, 651–655 (2002).10.1002/1521-4095(20020503)14:9<651::AID-ADMA651>3.0.CO;2-V ↗
17. Ciferri, A., Krigbaum, W. R. & Meyer, R. B. Polymer Liquid Crystals (Academic, New York, 1982).
18. Doi, M. & Edwards, S. F. The Theory of Polymer Dynamics (Clarendon, Oxford, 1986).
19. Elias, F., Clarke, S. M., Peck, R. & Terentjev, E. M. Equilibrium textures in main-chain liquid crystalline polymers. Europhys. Lett. 47, 442–448 (1999).10.1209/epl/i1999-00407-y ↗
20. Elias, F., Clarke, S. M., Peck, R. & Terentjev, E. M. Nematic order drives phase separation in polydisperse liquid crystalline polymers. Macromolecules 33, 2060–2068 (2000).10.1021/ma9916786 ↗
21. Landfester, K. Polyreactions in miniemulsions. Macromol. Rapid Commun. 22, 896–936 (2001).10.1002/1521-3927(20010801)22:12<896::AID-MARC896>3.0.CO;2-R ↗
22. Fridrikh, S. V. & Terentjev, E. M. Polydomain–monodomain transition in nematic elastomers. Phys. Rev. E 60, 1847–1857 (1999).10.1103/PhysRevE.60.1847 ↗