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MO: Fachverband Molekülphysik
MO 5: MO Poster 1
MO 5.14: Poster
Montag, 9. März 2020, 17:00–19:00, Empore Lichthof
phase transitions of nanoconfined water in self-assembled L,L-diphenylalanine peptides studied by vibrational spectroscopy — •Abuzer Orkun Aydin1, Ferid Salehli1, Svitlana Kopyl2, and Andrei Kholkin2 — 1Physics Department, Istanbul Technical University, Istanbul, Turkey — 2Physics Department and CICECO, Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
Self-assembly of diphenylalanine (FF) molecules results in highly organised tubular nanostructures. Water molecules are confined in FF rings with diameter about 1nm along these nanocavities. This work is a fresh look into phase behavior of nanoconfined water in natural synthetic biomacromolecule.
We obtained MIR spectra in the temperature range between 90K and 330 K. Five OH-stretching modes were identified in absorbance spectra as tetrahedral water in different confinements in FF rings, consequently (k1=3105 cm−1, k2=3150 cm−1, k3=3200 cm−1,k4=3275 cm−1) and non-completed tetrahedral water molecules between rings (k5=3375 cm−1). We found that these modes exhibit pronounced integral anomalies in the region of 195 K and 230 K, red shift and blue shift around 20 cm−1, consequently. First anomaly indicates the onset of long-range tetrahedral water order, whereas the second anomaly signifies the mentioned order. Three OH-bending modes at 1520 cm−1, 1515 cm−1 and 1620 cm−1 demonstrate redshift about 5 cm−1 around 230 K confirming the phase transition.