Progress in Understanding Fluids in Mesopores Harald Morgner Wilhelm Ostwald Institute for Physical and Theoretical Chemistry Leipzig University, Linnéstrasse 2, D Leipzig, Introduction to the phenomenon Theoretical: shortcomings of standard thermodynamics for confined systems new concept Applications: control of negative pressure (static, dynamic) molecular conformation, reaction rate, solvent properties, separation bioanalytics

Introduction Theoretical Applications behavior of fluids in mesopores natural phenomena hydrology of ground water natural purification and pollution industrial activities oil extraction mixture separation, filtering catalysis sensor development basic research bioanalytics

Introduction Theoretical Applications adsorption from vapor phase R.Rockmann PhD Thesis 2007 U Leipzig Adsorption Hysteresis in Porous Material SBA-15: silica pores with two open ends narrow pore size distribution

Introduction Theoretical Applications adsorption from vapor phase Adsorption Hysteresis in Porous Material H.Morgner 2010 J.Phys.Chem.C in press

Introduction Theoretical Applications computer simulation shape of pore isotherm of pores with two open ends crossing of grand potential curves gas reservoir adjusted gas density gas reservoir adjusted gas density treated explicitely in simulation pore wall

Introduction Theoretical Applications shortcomings of TD shape of pore isotherm of pores with two open ends crossing of grand potential curves observations: switching points decoupled from grand potential crossing switching points reproducibly stable in experiment and simulation „metastable“ states are stable in simulation and in experiment for any trial time (up to > 6 weeks) grand potential

Introduction Theoretical Applications new concept, confined TD COS and concept of applying canonical boundary conditions COS allow to retrieve isotherm grand canonical boundary conditions canonical boundary conditions

Pore with bottom

Pore with bottom, constant radius

Introduction Theoretical Applications new concept, confined TD Pore with bottom, narrow mouth curves of states (COS) homogeneous volume 3nm x31nm expanded liquid  neg. pressure, P< -100 bar

Introduction Theoretical Applications control of negative pressure negative pressure: exerts pull onto embedded molecule negative pressure is known for macroscopic systems, but metastable (e.g. A. R. Imre On the existence of negative pressure states, Phys. Stat. Sol. (b) 244 (2007) 893-9) in the nanoworld negative pressure states are stable and can be controlled, homogeneous negative pressure is taken on in volumes large enough to handle big (bio-)molecules for comparison: positive pressure of ~80bar turns CO 2 into polar solvent! what can -140bar do to influence molecular properties? molecular conformation reaction rate (large reaction volume) solvent properties separation of mixtures by inducing phase separation at neg. pressure Indirect methods to study liquid-liquid miscibility in binary liquids under negative pressure Imre, Attila R. et al. NATO Science Series, II: Mathematics, Physics and Chemistry (2007), 242 (Soft Matter under Exogenic Impacts),

Introduction Theoretical Applications negative pressure in stationary flow? for high throughput: continuous flow of solvent desirable can situation of negative pressure exist under stationary flow? the answer requires the ability to handle a velocity field

Introduction Theoretical Applications generalized diffusion Transport of Matter Common Treatment of Diffusion and Convection by generalized Diffusion single component: binary system: only one common driving force

Introduction Theoretical Applications negative pressure in stationary flow the answer: negative pressure can be held up under stationary flow! v=0.018cm/s => residence time in 100nm pore is ~500  s

Simulation: ejection of nanodroplet from mesopore t=1.21ms vol  6* l Introduction Theoretical Applications Bioanalytics