Surfaces and interfacial water: evidence that hydrophilic surfaces have long-range impact.

It is generally thought that the impact of surfaces on the contiguous aqueous phase extends to a distance of no more than a few water-molecule layers. Older studies, on the other hand, suggest a more extensive impact. We report here that colloidal and molecular solutes suspended in aqueous solution are profoundly and extensively excluded from the vicinity of various hydrophilic surfaces. The width of the solute-free zone is typically several hundred microns. Such large exclusion zones were observed in the vicinity of many types of surface including artificial and natural hydrogels, biological tissues, hydrophilic polymers, monolayers, and ion-exchange beads, as well as with a variety of solutes. Using microscopic observations, as well as measurements of electrical potential and UV-Vis absorption-spectra, infrared imaging, and NMR imaging, we find that the solute-free zone is a physically distinct and less mobile phase of water that can co-exist indefinitely with the contiguous solute-containing phase. The extensiveness of this modified zone is impressive, and carries broad implication for surface-molecule interactions in many realms, including cellular recognition, biomaterial-surface antifouling, bioseparation technologies, and other areas of biology, physics and chemistry.

[1]  Fumio Oosawa,et al.  Interaction between particles suspended in solutions of macromolecules , 1958 .

[2]  Hisae Yoshizawa,et al.  Fundamental mechanisms of interfacial friction. 2. Stick-slip friction of spherical and chain molecules , 1993 .

[3]  J. H. Cushman,et al.  On the Thermodynamic Stability of Confined Thin Films Under Shear , 1993, Science.

[4]  G. Ling,et al.  In Search of the Physical Basis of Life , 1984, Springer US.

[5]  T. Hashimoto,et al.  Void structure and vapor–liquid condensation in dilute deionized colloidal dispersions , 1995 .

[6]  W. Negendank.  Studies of ions and water in human lymphocytes. , 1982, Biochimica et biophysica acta.

[7]  B. Duenweg,et al.  散逸粒子動力学:平衡および非平衡分子動力学シミュレーションのための有用なサーモスタット(原標題は英語) , 2003 .

[8]  M. Robbins,et al.  Origin of Stick-Slip Motion in Boundary Lubrication , 1990, Science.

[9]  J. Israelachvili.  Intermolecular and surface forces , 1985 .

[10]  Hiroshi Nakamura,et al.  On the dynamic character of "ordered" structure in polymer latex suspensions , 1988 .

[11]  J. Henniker,et al.  The Depth of the Surface Zone of a Liquid , 1949 .

[12]  W. Tiller,et al.  The Structure Of Liquid Water; Novel Insights From Materials Research; Potential Relevance To Homeopathy , 2005, Indian Journal of Research in Homoeopathy.

[13]  L. R. Fisher,et al.  The Kelvin equation and the capillary condensation of water , 1981, Nature.

[14]  Patricia McGuiggan,et al.  Liquid to solidlike transitions of molecularly thin films under shear , 1990 .

[15]  Kaplan,et al.  Entropically driven surface phase separation in binary colloidal mixtures. , 1994, Physical review letters.

[16]  R. Pashley,et al.  Surface forces in adsorbed multilayers of water on quartz , 1979 .

[17]  Gerald H. Pollack,et al.  Cells, Gels and the Engines of Life: A New Unifying Approach to Cell Function , 2001 .

[18]  K. Ito,et al.  Inhomogeneity of solute distribution in ionic systems , 1990 .

[19]  P. Albertsson,et al.  Partition of Cell Particles and Macromolecules , 1986 .

[20]  H. Yoshida,et al.  Void Structure in Colloidal Dispersions , 1994, Science.

[21]  J. Crocker,et al.  ENTROPIC ATTRACTION AND REPULSION IN BINARY COLLOIDS PROBED WITH A LINE OPTICAL TWEEZER , 1999 .

[22]  B. Tata,et al.  How Homogeneous Are “Homogeneous Dispersions”? Counterion-Mediated Attraction between Like-Charged Species† , 1999 .

[23]  C. Heitner-Wirguin.  Recent advances in perfluorinated ionomer membranes : structure, properties and applications , 1996 .