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SUMMARY:Breathing Solids: from Human Hair to Designer Nanoporous Materials
  - Dr Alex Neimark\, Rutgers\, Rutgers University\, USA
DTSTART:20180608T130000Z
DTEND:20180608T140000Z
UID:TALK103828@talks.cam.ac.uk
CONTACT:Hilde Hambro
DESCRIPTION:Phenomenon of adsorption-induced deformation attracted recentl
 y a considerable attention owing to its relevance to practical problems of
  mechanical stability and integrity of novel nanoporous materials and thei
 r adsorption properties. Guest molecules adsorbed in nanopores cause a sub
 stantial stress in the host matrix leading to its swelling or contraction 
 depending on the specifics of host-guest interactions. Although various ex
 perimental manifestations of adsorption-induced deformation have been know
 n for a long time since Leonardo da Vinci’s studies of water sorption on
  human hair\, a rigorous theoretical description of this phenomenon is lac
 king. I will present a general thermodynamic approach to predicting adsorp
 tion stress and respective deformation in various microporous and mesoporo
 us materials based on molecular models of adsorption within elastic nanosc
 ale confinements. Examples include carbons\, zeolites\, mesoporous crystal
 s\, metal-organic frameworks\, and bio-inspired hierarchical nanoporous so
 lids.\n	A special attention will be paid to the enigmatic phenomenon of br
 eathing of metal-organic frameworks during gas adsorption-desorption cycle
 s illustrated in the figure.  Upon gas consumption\, the crystal first con
 tacts exhibiting a counter-intuitive abnormal "inhaling" transition from l
 arge pore (lp) phase to narrow pore (np) phase\, and then expands back to 
 lp phase that is associated with normal "inhaling". On the desorption pass
 \, the reverse normal lp-np and abnormal np-lp “exhaling” transitions 
 take place with a prominent hysteresis. Breathing solids are currently wid
 ely explored as actuators\, sensors\, selective adsorbents\, and drug deli
 very vehicles.\nLiterature:\n1. P.I. Ravikovitch and A. V. Neimark\, - Den
 sity Functional Theory Model of Adsorption Deformation\, Langmuir\, 2006\,
  22\, 11171.\n2. A.V. Neimark\, F.-X. Coudert\, A. Boutin\, A.H. Fuchs\, S
 tress-based Model for the Breathing of Metal–Organic Frameworks\, JPC Le
 tters\, 2010\, 1\, 445.\n3. C. Triguero\, F.-X. Coudert\, A. Boutin\, A.H.
  Fuchs\, A.V. Neimark\, Mechanism of Breathing Transitions in Metal-Organi
 c Frameworks\, JPC Letters\, 2011\, 2\, 2033.\n4. G.Yu. Gor and A.V. Neima
 rk\, - Adsorption-Induced Deformation of Mesoporous Solids: Macroscopic Ap
 proach and Density Functional Theory\, Langmuir\, 2011\, 27\, 6926.\n5. A.
 V. Neimark\, F.X. Coudert\, C. Triguero\, A. Boutin\, A.H. Fuchs\, I. Beur
 roies\, and R. Denoyel\, - Structural Transitions in MIL-53 (Cr): View fro
 m Outside and Inside\, Langmuir\, 2011\, 27\, 4734.\n6. F.-X. Coudert\, A 
 H. Fuchs\, A. Boutin\, and A.V. Neimark\, Adsorption Deformation and Struc
 tural Transitions in Metal-Organic Frameworks: From the Unit Cell to the C
 rystal\, JPC Letters\, 2013\, 4\, 3198.\n7. F.-X. Coudert\, A.H. Fuchs\, a
 nd A.V. Neimark\, Adsorption Deformation of Microporous Composites\, Dalto
 n Transactions\, 2016\, 45\, 4136. \n8. C. Balzer\, R. Cimino\, G Y. Gor\,
  A.V. Neimark\, and G. Reichenauer\, Deformation of microporous carbons du
 ring N2\, Ar\, and CO2 adsorption: Insight from the density functional the
 ory\, Langmuir\, 2016\, 2\, 8265.\n9. C. Balzer\, A.M. Waag\, S. Gehret\, 
 G. Reichenauer\, R. Morak\, L. Ludescher\, F. Putz\, N. Hüsing\, O. Paris
 \, N. Bernstein\, G.Y. Gor\, and A.V. Neimark\, Adsorption-Induced Deforma
 tion of Hierarchically Structured Mesoporous Silica - Effect of Pore-Level
  Anisotropy\, Langmuir\, 2017\, V.33\, p.5592-5602.\n
LOCATION:Oatley Seminar Room\, Department of Engineering
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