A series of polypeptides, poly(ε-benzyloxycarbonyl-L-lysine) (PZLys), has been synthesized. The self-assembly of the PZLys was studied by using differential scanning calorimetry (DSC), Fourier transform infrared radiation spectroscopy (FTIR), small-angle X-ray scattering (SAXS) and polarizing optical microscopy (POM). The structural variations can be manipulated not only via the change of chain length but also various thermal treatments. The transformation of secondary structures from α-helix to β-sheet and the reversibility of supramolecular organization were examined. The conformational transformation between α-helix and β-sheet is expected to be strongly affected by the intra- and inter-molecular hydrogen bonding of polypeptide chains. The transformation of the secondary structures was found to be thermally irreversible by temperature-dependent FTIR. For high-molecular-weight polypeptides, the β-sheet conformation is destabilized in favor of the α-helical conformation, because the intra-molecular hydrogen bonds stabilize the α-helical conformations. As successively cooling and heating process, the structural evolution from secondary structures to tertiary structures revealed a reversible route and as a function of temperature which was investigated by temperature-dependent SAXS. In the tertiary textures, the dimension of the hexagonally packed α-helical structures exhibit thermally reversible behavior. With a decrease of molecular weight of polypeptides, β-sheet lamellae structures can be found in addition to hexagonal packing of α-helical organization and reveal similar thermal reversibility. The size of the β-sheet lamellar structures that is calculated from half-height width of Bragg peaks by Scherrer formula also changes with temperature. At high temperature, β-sheet conformation is stabilized by inter-molecular hydrogen bonding and contributes to the lamellar assembly of β-sheets, thus the size of β-sheet lamellar structures is thickened. In addition, shear-induced oriented samples were obtained and exhibited similar thermal reversibility in the tertiary structure. Only β-sheet lamellar structure is identified for oriented low-molecular-weight polypeptides, because the minor unstably hexagonal packing of α-helical organization is easily broken by external stress. Subsequently, specific textures are examined in quaternary structures by POM while β-sheet lamellar structures are formed from low-molecular-weight polypeptides. Results show that the textures start to develop at the transition temperature, i.e., from α-helix to β-sheet, and remain unchanged up to the thermal decomposition temperature.
Furthermore, novel nanostructures from self-assembly through secondary forces such as hydrogen bonding in the peptide-based diblock copolymer, poly(ε-benzyloxycarbonyl-L-lysine)-poly(L-Lactide acid) (PZLys-PLLA), were investigated. The secondary structures of PZLys-PLLA also possessed both of α-helical and β-sheet conformations. The lamellar-like structures have been observed by TEM. However, no Bragg peaks are observed in SAXS pattern because of the only slight difference of electron density between PZLys and PLLA blocks. The currently observed structural characteristics in PZLys-PLLA may serve as a basis for future studies.

1.Whitesides, G. M.; Grzybowski, B. Science 2002, 295, 2418-2421.
2.Philip, D.; Stoddart, J. F. Angew. Chem., Int. Ed. Engl. 1996, 35, 1154-1196.
3.Deng, T.; Chenb,C.; Honekerb,C.; Thomas, E. L. Polymer 2003, 44, 6549-6553.
4.Muthukumar, M.; Ober, C. K., Thomas, E. L. Science 2002, 277, 1225-1232.
5.Lehn, J.-M. Supramolecular Chemistry; VCH: Weinheim, Germany, 1995.
6.Lehn, J.-M. Science 2002, 295, 2400-2409.
7.Barboiu, M.; Vaughan, G.; Kyritsakas, N.; Lehn, J.-M. Chem. Eur. J. 2003, 9, 763-769.
8.Kato, T. Science 2002, 295, 2414-2418.
9.Kanie, K.; Yasuda, T.; Ujiie, S.; Kato, T. Chem. Commun. 2000, 19, 1899-1900.
10.Kanie, K.; Nishii, M.; Yasuda, T.; Taki, T.; Ujiie, S.; Kato, T. J. Mater. Chem., 2001, 11, 2875–2886.
11.Kato, T.; Matsuoka, T.;Nishii, M.; Kamikawa,Y.; Kanie,K.; Nishimura,T.; Yashima, E.; Ujiie, S. Angew. Chem. Int. Ed. 2004, 43, 1969-1972.
12.Schenning, A. P. H. J.; Herrikhuyzen, J. V.; Jonkheijm, P.; Chen, Z.; WJrthner, F.; Meijer, E. W. J. Am. Chem. Soc. 2002, 124, 10252-10253.
13.Bates, F. S. & Fredrickson, G. H. Phys. Today 1997, 32-38.
14.Bates, F. S. Science 1991, 251, 898-904.
15.Boontongkong, Y. & Cohen,R. E. Macromolecules 2002, 35, 3647-3652.
16.Chan, V. Z.-H. et al. Science 1999, 286, 1716-1719.
17.Rockford, L. et al. Phys. Rev. Lett. 1999, 22, 2602-2605.
18.Lipic, P. M., Bates, F. S. & Hillmyer, M. A. J. Am. Chem. Soc. 1999, 120, 8963-8970.
19.Förster, S. & Antonietti, M. Adv. Mater. 1998, 10, 195-217.
20.Park, M., Harrison, C., Chaikin, P. M., Register, R. A. & Adamson, D. H. Science 1997, 276, 1401-1404.
21.Fogg, D. E.; Radzilowski, L. H.; Balnski, R.; Schrock, R. R.; Thomas, E. L. Macromolecules 1997, 30, 417.
22.Harada, A.; Kataoka, K. Science 1999, 283, 65.
23.(a) Cornelissen, J. J. L. M.; Fischer, M.; Sommerdijk, N. A. J. M.; Nolte, R. J. M. Science 1998, 280, 1427-1430. (b) Engelkamp, H.; Middelbeek, S.; Nolte, R. J. M. Science 1999, 284, 785-788.
24.Cornelissen, J. J. L. M.; Donners, J. J. J. M.; de Gelder, R.; Graswinckel, W. S.; Metselaar, G. A.; Rowan, A. E.; Sommerdijk, N. A. J. M.; Nolte, R. J. M. Science 2001, 293, 676.
25.Cha, J. N.; Stucky, G. D.; Morse, D. E.; Deming, T. J. Nature, 2000, 403, 289.
26.Klok, H.-A.; Lecommandoux, S. Adv. Mater. 2001, 13, 1217.
27.Gallot, B. Prog. Polym. Sci. 1996, 21, 1035
28.P.D. Bailey Peptide Chemistry ; Wiley, 1990.
29.Ramachandran GN, Ramakrishnan C, Sasisekharan V. Stereochemistry of Polypeptide Chain Configurations. J Mol Biol 1963; 7, 95-99.
30.Ramachandran GN, Sasisekharan V. Conformation of polypeptides and proteins. Adv Prot Chem 1968; 23, 284-438.
31.Pauling L, Corey RB, Branson HR. The Structure of Proteins: Two Hydrogen-Bonded Helical Configurations of the Polypeptide Chain. Proc Nat Acad Sci USA 1951a; 37, 205-211.
32.Pauling L, Corey RB. Configurations of Polypeptide Chains with Favored Orientations Around Single Bonds: Two New Pleated Sheets. Proc Nat Acad Sci USA 1951b; 37, 729-740.
33.Romero Colomer, F.; Gomes Ribelles, J. L. Polymer 1989, 30, 849.
34.Romero Colomer, F. J.; Gomez Ribelles, J. L.; Barrales-Rienda, J. M. Macromolecules 1994, 27, 5004.
35.Romero Colomer, F.; Gomes Ribelles, J. L.; Lloveros Macia, J.; Guerra Munoz, S. Polymer 1991, 32, 1642.
36.Watanabe, J.; Uematsu, I. Polymer 1984, 25, 1711.
37.Schmidt, A.; Lehmann, S.; Georgelin, M.; Katana, G.; Mathauer, K.; Kremer, F.; Schmidt-Rohr, K.; Boeffel, C.; Wegner, G.; Knoll, W. Macromolecules 1995, 28, 5487.
38.Hartmann, L.; Kratzmuller, T.; Braun, H.-G.; Kremer, F. Macromol. Rapid Commun. 2000, 21, 814.
39.Wang, C.; Pecora, R. J. Chem. Phys. 1980, 72, 5333.
40.Papadopoulos, G. Floudas, H.-A. Klok, I. Schnell, and T. Pakula, Biomacromolecules 2004, 5, 81
41.Hamley, I. W. The Physics of Block Copolymers; VCH: Oxford University, New York, 1998.
42.Bates, F. S.; Fredrickson, G. H. Annu. Rev. Phys. Chem. 1990, 41, 525-557.
43.G. Riess, C. Hurtez, P. Badahur, “Block Copolymers”, in Encyclopedia of Polymer Science and Engineering, 2nd ed., Vol. 2 (Ed: J. L. Kroschwitz), Wiley, New York 1985.
44.a) J. T. Chen, E. L. Thomas, C. G. Zimba, J. F. Rabolt, Macromolecules 1995, 28, 5811. b) A. Urbas, Y. Fink, E. L. Thomas, Macromolecules 1999, 32, 4748. c) Y. Fink, A. M. Urbas, M. G. Bawendi, J. D. Joannopoulos, E. L. Thomas, J. Lightwave Technol. 1999, 11, 1963.
45.A. Urbas, R. Sharp, Y. Fink, E. L. Thomas, M. Xenidou, L. J. Fetters, Adv. Mater. 2000, 12, 812.
46.a) T. Goldacker, V. Abetz, R. Stadler, I. Erukhimovich, L. Leibler, Nature 1999, 398, 137. b) V. Abetz, T. Goldacker, Macromol. Rapid Commun. 2000, 21, 16.
47.a) G. Liu, J. Ding, A. Guo, M. Herfort, D. Bazett-Jones, Macromolecules 1997, 30, 1851. b) G. Liu, J. Ding, Adv. Mater. 1998, 10, 69. c) G. Liu, J. Ding, T. Hashimoto, K. Kimishima, F. M. Winnik, S. Sigam, Chem. Mater. 1999, 11, 2233.
48.G. Liu, J. Ding, S. Stewart, Angew. Chem. Int. Ed. 1999, 38, 835.
49.a) F. S. Bates, M. F. Schulz, J. H. Rosedale, K. Almdal, Macromolecules 1992, 25, 5547. b) C. Singh, M. Goulian, A. J. Liu, G. H. Fredrickson, Macromolecules 1994, 27, 2974. c) M. W. Matsen, J. Chem. Phys. 1996, 104, 7758.
50.G. Mao, C. K. Ober, Acta Polym. 1997, 48, 405.
51.a) J. T. Chen, E. L. Thomas, C. K. Ober, S. S. Hwang, Macromolecules 1995, 28, 1688. b) J. T. Chen, E. L. Thomas, C. K. Ober, G.-P. Mao, Science 1996, 273, 343.
52.Bates, F. S.; Schulz, M. F.; Rosedale, J. H.; Almdal, K. Macromolecules 1992, 25, 5547. (b) Singh, C.; Goulian, M.; Liu, A. J.; Fredrickson, G. H. Macromolecules 1994, 27, 2974.
53.a) S. M. Yu, V. P. Conticello, G. Zhang, C. Kayser, M. J. Fournier, T. L. Mason, D. A. Tirrell, Nature 1997, 389, 167. b) S. M. Yu, C. H. Soto, D. A. Tirrell, J. Am. Chem. Soc. 2000, 122, 6552.
54.S. I. Stupp, V. LeBonheur, K. Walker, L. S. Li, K. E. Huggins, M. Keser, A. Amstutz, Science 1997, 276, 384.
55.These mushroom-shaped nanostructures can be converted into macromolecular objects while retaining size and shape via crosslinking of the oligo(butadiene) segment: E. R. Zubarev, M. U. Pralle, L. Li, S. I. Stupp, Science 1999, 283, 523.
56.a) S. I. Stupp, V. LeBonheur, K. Walker, L. S. Li, K. E. Huggins, M. Keser, A. Amstutz, Science 1997, 276, 384. b) G. N. Tew, L. Li, S. I. Stupp, J. Am. Chem. Soc. 1998, 120, 5601. c) M. U. Pralle, K. Urayama, G. N. Tew, D. Neher, G. Wegner, S. I. Stupp, Angew. Chem. Int. Ed. 2000, 39, 1486.
57.J. J. L. M. Cornelissen, M. Fischer, N. A. J. M. Sommerdijk, R. J. M. Nolte, Science 1998, 280, 1427.
58.T. Hayashi, A. G. Walton and J. M. Anderson, Macromolecules 1977, 10, 346.
59.T. Hayashi, A. G. Walton and J. M. Anderson, Macromolecules 1977, 10, 352.
60.F. Urallil, T. Hayashi, J. M. Anderson and A. Hiltner, Polym. Eng. Sci. 1977, 17, 515.
61.A. Douy and B. Gallot, ACS Ser. 1978, 74, 165.
62.A. Douy and B. Gallot, Polymer 1987, 28, 147.
63.AB diblock copolymers (A = peptide block). See, e.g.: a) J.-P. Billot, A. Douy, B. Gallot, Makromol. Chem. 1976, 177, 1889. b) J.-P. Billot, A. Douy, B. Gallot, Makromol. Chem. 1977, 178, 1641. c) A. Douy, B. Gallot, Polym. Eng. Sci. 1977, 17, 523. d) A. Douy, B. Gallot, Polymer 1982, 23, 1039. e) G. P. Vlasov, G. D. Rudkovskaya, L. A. Ovsyannikova, Makromol. Chem. 1982, 183, 2635. f) I. Hattori, A. Hirao, K. Yamaguchi, S. Nakahama, N. Yamazaki, Makromol. Chem. 1983, 184, 1355.
64.ABA triblock copolymers (A = peptide block). See, e.g.: a) A. Nakajima, T. Hayashi, K. Kugo, K. Shinoda, Macromolecules 1979, 12, 840. b) A. Nakajima, K. Kugo, T. Hayashi, Macromolecules 1979, 12, 844. c) S. Barenberg, J. M. Anderson, P. H. Geil, Int. J. Biol. Macromol. 1981, 3, 82. d) Y. Imanishi, M. Tanaka, C. H. Bamford, Int. J. Biol. Macromol. 1985, 7, 89. e) C.-S. Cho, S.-W. Kim, T. Komoto, Makromol. Chem. 1990, 191, 981. f) C.-S. Cho, B.-W. Jo, J.-K. Kwon, T. Komoto, Macromol. Chem. Phys. 1994, 195, 2195.
65.a) H. Block, Poly(γ-benzyl-L-glutamate) and Other Glutamic Acid Containing Polymers, Gordon and Breach, New York 1983 (poly(γ-benzyl-Lglutamate)). b) G. D. Fasman, M. Idelson, E. R. Blout, J. Am. Chem. Soc. 1961, 83, 709 (poly(ε-benzyloxycarbonyl-L-lysine)).
66.Schlaad H, Smarsly B, Losik M Macromolecules 2004, 37, 2210-2214.
67.a) H.-A. Klok, J. F. Langenwalter, S. Lecommandoux, Macromolecules 2000, 33, 7819.
68.Lecommandoux, S.; Achard, M.-F.; Langenwalter, J. F.; Klok, H.-A. Macromolecules 2001, 34, 9100-9111.
69.For some recent publications, see e.g.: (a) Stupp, S. I.; LeBonheur, V.; Walker, K.; Li, L. S.; Huggins, K. E.; Keser, M.; Amstutz, A. Science 1997, 276, 384. (b) Lee, M.; Cho, B.- K.; Kim, H.; Zin, W.-C. Angew. Chem., Int. Ed. Engl. 1998, 37, 638. (c) Jenekhe, S. A.; Chen, X. L. Science 1999, 283, 372.
70.Checot, F.; Lecommandoux, S.; Gnanou, Y.; Klok, H. A. Angew. Chem., Int. Ed. 2002, 41, 1339.
71.Hafkamp, R. J. H. et al. Chem. Commun. 1997, 545-546.
72.Tachibana, T. & Kambara, H. J. Am. Chem. Soc. 1965, 87, 3015-3016.
73.Rowan, A. E. & Nolte, R. J. M. Angew. Chem., Int. Ed. 1998, 37, 63-68.
74.Feiters, M. C. & Nolte, R. J. M. Advances in Supramolecular Chemistry. 1965, 6, 41-156.
75.Ho, R.-M.; Chiang, Y. W.; Tsai, C. C.; Lin, C. C.; Ko, B. T.; Huang, B.-H. J. Am. Chem. Soc. 2004, 126, 2704.
76.Yuki, H. Nippon Kagaku Zasshi. 1956, 77, 44-54
77.Watanabe, J.; Uematsu, I. Polymer 1984, 25, 1711-1717
78.Blout, E. R.; Asadourian, A. J. Am. Chem. Soc. 1956, 78, 955.
79.M. Kobayashi, K. Akita, and H. Tadokoro, Makromol. Chem. 1968, 118, 324.
80.H. Tadokoro, N. Nishiyama, S. Nozakura, and S. Murahashi, J. Polym. Sci. 1959, 36, 553.
81.Duan YX, Zhang JM, Shen DY, Macromolecules 2003, 36, 4874-4879