Some Thoughts on the Hydrophobic Interaction P. Pincus Physics, Materials, Biomolecular Science & Engineering UCSB “The magnitude, range and origin of.

Slides:

Advertisements

Similar presentations

ILCC Edinburgh, July 2002 VAN DER WAALS INTERACTION AND STABILITY OF MULTILAYERED LIQUID-CRYSTALLINE SYSTEMS dr. Andreja [ arlah Univerza v Ljubljani.

Advertisements

Biochemistry 4511 Chapter 2 Water Chapter 2 Water revised 8/26/2013.

Science & Technology Multiscale Modeling of Lipid Bilayer Interactions with Solid Substrates David R. Heine, Aravind R. Rammohan, and Jitendra Balakrishnan.

Computational Issues in Modeling Ion Transport in Biological Channels: Self- Consistent Particle-Based Simulations S. Aboud 1,2, M. Saraniti 1,2 and R.

Lecture 14: Special interactions. What did we cover in the last lecture? Restricted motion of molecules near a surface results in a repulsive force which.

Solutions and Water Structure. Properties of solutions Water microstructure Solute microstructure –Ionic solutes –Polar solutes –Nonpolar solutes (the.

Solutions. Topics  Solution process  Saturated, unsaturated, supersaturated  Miscibility, solubility  Hydrophobic, hydrophilic  Hydration, solvation.

Physical chemistry of solid surfaces

Properties of Water Ocean motions governed by fundamental physical laws of conservation of mass, momentum and energy Water’s truly unique property as related.

Chapter 13: Control of Solubility Many of the forces we’ve talked about occur between ions/molecules in solutions Definition: A homogeneous mixture (only.

Protein Primer. Outline n Protein representations n Structure of Proteins Structure of Proteins –Primary: amino acid sequence –Secondary:  -helices &

1 The Chemical basis for Life (continued) What holds atoms together? Ionic bonds  Attraction between oppositely charged ions (atoms or molecules)  Weak.

Introduction to Statistical Thermodynamics of Soft and Biological Matter Lecture 4 Diffusion Random walk. Diffusion. Einstein relation. Diffusion equation.

Lecture 2: Forces and Potentials. What did we cover in the last lecture? Microscopic and nanoscale forces are important in a number of areas of nanoscience,

Surface and Interface Chemistry  Thermodynamics of Surfaces (LG and LL Interfaces) Valentim M. B. Nunes Engineering Unit of IPT 2014.

Dispersed Systems FDSC Version. Goals Scales and Types of Structure in Food Surface Tension Curved Surfaces Surface Active Materials Charged Surfaces.

Industrial Chemistry Part ii

How H 2 0 interacts with: Itself –Hydrogen-bonding Ions and charged functional groups –Solvation, screening, dielectric value Non-polar groups –The hydrophobic.

October 18, 2010 Obj: Understand water’s unique chemical properties. Warm-Up: Why is water a polar molecule? (Answer this in your notebook.) 1.

Ch. 11: Liquids, Solids, and Intermolecular Forces Dr. Namphol Sinkaset Chem 200: General Chemistry I.

Biomaterials and Protein Adsorption

Theories of Polyelectrolytes in Solutions

Chapter 14: Solutions Many of the forces we’ve talked about occur between ions/molecules in solutions Definition: A homogeneous mixture (only one phase)

2-3: WATER + SOLUTIONS  The chemical reactions of all living things take place in an aqueous environment (i.e. WATER)  Let’s look at some of the unique.

§8.4 Surface adsorption of solution. 1 The surface phenomena of solution: Is solution homogeneous? (1) surface adsorption AA A B A B Solvent A Solute.

Chapter 2-3 Water and Solutions

Micelle A micelle (rarely micella, plural micellae) is an aggregate of surfactant molecules dispersed in a liquid colloid. A typical micelle in aqueous.

CH. 3 ~ CELLS. Cell Membrane 1.Surrounds ALL cells 2.Has a “Phospholipid bilayer” which makes it “flexible and “fluid”

 Water molecules are formed by covalent bonds that link two hydrogen (H) atoms to one oxygen (O) atom.  Water molecules have a slightly positive.

Cohesion and Surface Tension. Cohesion Cohesion Molecules are attracted to other molecules of the same kind. ◦ For example, as you can see from the picture.

3.052 Nanomechanics of Materials and Biomaterials Prof. Christine Ortiz DMSE, RM Phone : (617) WWW :

INTERACTIONS IN PROTEINS AND THEIR ROLE IN STRUCTURE FORMATION.

Covalent interactions non-covalent interactions + = structural stability of (bio)polymers in the operative molecular environment 1 Energy, entropy and.

Lecture 5 Interactions Introduction to Statistical Thermodynamics

Introduction to Dispersed Systems FDSC400 09/28/2001.

Capillary force between particles: Force mediated by a fluid interface Interactions between Particles with an Undulated Contact Line at a Fluid Interface:

Homework 2 (due We, Feb. 1): Reading: Van Holde, Chapter 1 Van Holde Chapter 3.1 to 3.3 Van Holde Chapter 2 (we’ll go through Chapters 1 and 3 first. 1.Van.

Lecture 5 Barometric formula and the Boltzmann equation (continued) Notions on Entropy and Free Energy Intermolecular interactions: Electrostatics.

IM/VdW forces are the forces of attraction between molecules – not within the molecule. VdW forces vary in strength depending on the interactions between.

Adsorption of geses on liquids. Surface-active and surface-inactive substances. Gibbs’s equation, Shyshkovsky’s equations and Langmuir’s equations Plan.

What is life’s chemical basis? Atoms – Fundamental building blocks of matter Nucleus – Positively charged protons – Uncharged neutrons (except for hydrogen)

Membrane Structure and Function. What is the Function of The Plasma Membrane? Boundary Must be selectively permeable.

The origin of attractive interactions between DNA molecules Author: Matej Kanduč Mentor: prof. Rudi Podgornik.

Intermolecular Interactions

 SWBAT summarize what causes surface tension in water.  SWBAT define solution, solute, solvent and polar molecule.  SWBAT summarize the steps of dissolving.

Semi-Empirical Mass Formula part I Classical Terms [Sec. 4.2 Dunlap]

1 Chapter 7 Continued: Entropic Forces at Work (Jan. 10, 2011) Mechanisms that produce entropic forces: in a gas: the pressure in a cell: the osmotic pressure.

PROPERTIES OF WATER Chapter 6.3. Water A water Molecules is made of Two Hydrogen atoms and an Oxygen atom H 2 0 O.

Biology 102 Lecture 3: Atoms, molecules and life (cont.)

Outline The Nature of Noncovalent Interactions

Surface Adhesion and Water Drops Low Surface Adhesion High Surface Adhesion Water molecules attracted to each other (hydrogen bonding) and not to the surface.

5.1- Compounds and Molecules I can: -explain atoms may be bonded together by losing, gaining or sharing electrons to form molecules or three-dimensional.

Describe why hydrogen bonding in water is important Explain why water is such a good solvent (example: salt dissolving in water) Describe the difference.

General Biology Properties of Water. I. Water is an important topic to biologists Life on earth probably evolved in water. Life on earth probably evolved.

Aim: What attraction forces exist among neighboring molecules? I.O.SWBAT: 1)Use the KMT to explain the differences in motion of particles in the gas, liquid,

Properties of Water Biochemistry. Why is Water Important? Habitat Transport medium Some metabolic reactions Cell shape homeostasis.

Water, Water Everywhere! Essential Questions: What are the properties of Water? What are Mixtures, Solutions and Suspensions? Why is water important for.

6.3 Water and Solutions.

Water and its unique properties

Making solutions In order to dissolve - the solvent molecules must come in contact with the solute. Stirring moves fresh solvent next to the solute. The.

Chapter 11 Liquids, solids, and intermolecular forces

Water, Water Everywhere!

Chemistry of Biology.

Cartilage Aggrecan Can Undergo Self-Adhesion

Making solutions In order to dissolve - the solvent molecules must come in contact with the solute. Stirring moves fresh solvent next to the solute. The.

Chapter 11 Liquids, solids, and intermolecular forces

How Does a Voltage Sensor Interact with a Lipid Bilayer

§8.4 Surface adsorption of solution

Counterion Condensation and Collapse of Polyelectrolyte Chains

Cartilage Aggrecan Can Undergo Self-Adhesion

Presentation transcript:

Some Thoughts on the Hydrophobic Interaction P. Pincus Physics, Materials, Biomolecular Science & Engineering UCSB “The magnitude, range and origin of the hydrophobic interaction have been a mystery ever since the pioneering work by Kauzman and Tanford…….” J. Israelachvili, 2005

What is it?  Strong short range (~ 1 nm) attractive force between hydrophobic surfaces in water (Tanford, Clausson, Wennerstrøm, F. Evans …….)  Why oil is insoluble in water. ARE THESE UNRELATED?

OUTLINE  Interfaces – Patches E. Meyer, Q. Lin, J. Israelachvili (Israelachvili Group) A. Naydenov, P. Pincus  Molecules – H-Bonding Network Disruption D. Hone, P. Pincus

ISRAELACHVILI PROTOCOL Surface force apparatus with mica substrate Mica is highly Hydrophilic and Anionic – σ = 1e/nm 2 100nm<h< 0.1nm  Passivate with cationic surfactant DODAB – Langmuir Deposition  Measure forces with SFA  Look at surfaces with AFM

AFM IMAGES Ch. Rotsch & Manfred Radmacher--LMU Patchy surface - nearly mixture of bilayers and bare mica Broad distribution of patches– ten’s of nanometers

UCSB AFM Hansma Lab Air Water

Forces Representative data for the normalized force vs distance curves for two DODA monolayer-coated mica surfaces ( ○ ) and for a DODA surface and a bare mica surface (●). Consistent with 1/r at short distances

DISJOINING PRESSURE  Negative mobile holes  Positive bilayer matrix L ~ nm-μm Bloomfield –Rouzina Attraction on L Scale Range scales with L ~ 20 nm Coulombic correlation between positive and negative patches on opposing surfaces

MONOLAYER INSTABILITY Gain in water/oil surface energy is sufficient to overcome screened Coulomb attraction. But why not complete segregation? Counterion Release

HOMOGENEOUSLY CHARGED SURFACE Gauss’ Law => φ x Electrostatic Potential φ = T(x/λ) Gouy-Chapman Length λ = (4πσℓ) -1 Bjerrum Length ℓ = e 2 /εT ≈ 0.6 nm in water All counterions bound to sheath of thickness λ !

ENTROPY DRIVEN PATCHES φ( X) X L T(L/λ) Patch size given by balance of counterion release against line tension of patches. Broad patch distribution L~λ ln[(ζ/T)(c s λ 2 ) -1 ] ζ is line tension, c s is salt concentration

PASSIVATED MICA VS BARE MICA Experimental evidence for patch mobility!

What is it?  Strong short range (~ 1 nm) attractive force between hydrophobic surfaces in water (Tanford, Clausson, Wennerstrøm, F. Evans …….)  Why oil is insoluble in water. ARE THESE UNRELATED?

H-BONDING IN WATER V U O -- U > V Polarizability of hydroxy l hydronium ions/cm 3 => U~20 k B T t H-bond energy ~ -t 2 /(2U) ~ 5 k B T SP hybridization

MOLECULAR HYDROPHOBIC INTERACTTION Non-H bonding impurity --- alkyl chain Cost in H bonding energy = zt 2 /U Z is coordination number Nearest neighbor impurities gain t 2 /U ~ 5 T!!! Disruption of H-bonding network Chandler et al

TAKE-HOME MESSAGE  Electrostatic coupling between charged domains in proteins and other biopolymer, membrane systems  Patches stabilized by counterion release  Hydrogen bond network disruption in molecular systems  No unique “hydrophobic interaction”….