FT-IR Study of the Interlamellar Water Confined in Glycolipid Nanotube Walls Yanli Guo, † Hiroharu Yui,* ,†,‡ Hiroyuki Minamikawa, ‡,§ Mitsutoshi Masuda, ‡,§ Shoko Kamiya, ‡ Tsuguo Sawada, † Kohzo Ito, † and Toshimi Shimizu* ,‡,§ Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan, CREST, Japan Science and Technology Agency (JST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan, and Nanoarchitectonics Research Center (NARC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan Received December 15, 2004. In Final Form: February 15, 2005 The local hydrogen-bonding environment of water confined in glycolipid nanotubes (LNTs) was investigated by Fourier transform infrared (FT-IR) spectroscopy. Using X-ray diffraction (XRD), we estimated the thickness of an interlamellar water layer, which was confined between the bilayer membranes constructing the walls of the LNTs, to be 1.3 ( 0.3 nm. FT-IR spectroscopic measurement of the confined water showed an obvious reduction in IR absorption in both the low-energy (around 3000 cm -1 ) and high-energy regions (around 3600 cm -1 ) of the OH stretching band as compared to bulk water. The reduction around 3000 cm -1 indicated a decrease in the relative proportion of the water molecules with a long-range network structure due to a geometrical restriction. This agrees with the results obtained for other multilamellar systems. On the other hand, the remarkable reduction around 3600 cm -1 , which was not observed in the other systems, indicated the absence of weakly hydrogen-bonded water aggregates due to the effect of sugar headgroups. Introduction Studies on the structure and dynamics of water molecules confined in restricted geometries are of great interest, since the confined water plays an important role in biological and geological systems. 1-5 In the past two decades, water confined either in the cores of spherical reversed micelles (Figure 1a) or between the layers of various lamellar structures (Figure 1b,c) has been widely studied by a variety of experimental and computer simulation methods. 6-17 Infrared (IR) and Raman spec- troscopic experiments have demonstrated that the char- acteristics of confined water with dimensions of a few nanometers obviously differ from those of bulk water. The deviation is derived from the size confinement and the effect of the polar headgroups of amphiphiles. Several research groups have examined the effect of size confine- * To whom correspondence should be addressed. E-mail: yui@ molle.k.u-tokyo.ac.jp (H.Y.); tshmz-shimizu@aist.go.jp (T.S.). † The University of Tokyo. ‡ Japan Science and Technology Agency (JST). § National Institute of Advanced Industrial Science and Tech- nology (AIST). (1) Marechal, Y.; Chamel, A. J. Phys. Chem. 1996, 100, 8551-8555. (2) Chapman, D. J. Food Eng. 1994, 22, 367-380. (3) Costanzo, P. M.; Giese, R. F.; Lipsicas, M.; Straley, C. Nature 1982, 296, 549-551. (4) Pitteloud, C.; Powell, D. H.; Gonzalez, M. A.; Cuello, G. J. Colloids Surf., A 2003, 217, 129-136. (5) Yui, H.; Guo, Y.; Koyama, K.; Sawada, T.; John, G.; Yang, B.; Masuda, M.; Shimizu, T. Langmuir 2005, 21, 721-727. (6) Macdonald, H.; Bedwell, B.; Gulari, E. Langmuir 1986, 2, 704- 708. (7) Onori, G.; Santucci, A. J. Phys. Chem. 1993, 97, 5430-5434. (8) Jain, T. K.; Varshney, M.; Maitra, A. J. Phys. Chem. 1989, 93, 7409-7416. (9) Li, Q.; Weng, S. F.; Wu, J. G.; Zhou, N. F. J. Phys. Chem. B 1998, 102, 3168-3174. (10) Zhou, N. F.; Li, Q.; Wu, J. G.; Chen, J.; Weng, S. F.; Xu, G. X. Langmuir 2001, 17, 4505-4509. (11) Brubach, J. B.; Mermet, A.; Filabozzi, A.; Gerschel, A.; Lairez, D.; Krafft, M. P.; Roy, P. J. Phys. Chem. B 2001, 105, 430-435. (12) Umemura, J.; Matsumoto, M.; Kawai, T.; Takenaka, T. Can. J. Chem. 1985, 63, 1713-1718. (13) Lhert, F.; Capelle, F.; Blaudez, D.; Heywang, C.; Turlet, J. M. J. Phys. Chem. B 2000, 104, 11704-11707. (14) Berger, C.; Desbat, B.; Kellay, H.; Turlet, J. M.; Blaudez, D. Langmuir 2003, 19,1-5. (15) Scott, H. L. Chem. Phys. Lett. 1984, 109, 570-573. (16) Lafleur, M.; Pigeon, M.; Pezolet, M.; Caille, J. P. J. Phys. Chem. 1989, 93, 1522-1526. (17) Boissiere, C.; Brubach, J. B.; Mermet, A.; de Marzi, G.; Bourgaux, C.; Prouzet, E.; Roy, P. J. Phys. Chem. B 2002, 106, 1032-1035. Figure 1. Schematic diagrams of water confined in several representative molecular aggregates: (a) reversed spherical micelle; (b) black soap film; (c) multilamellar structure; (d) glycolipid nanotube (LNT). 4610 Langmuir 2005, 21, 4610-4614 10.1021/la046906q CCC: $30.25 © 2005 American Chemical Society Published on Web 04/16/2005