Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	How does a star chain (nanooctopus) crawl through a nanopore?
Δημιουργός/Συγγραφέας:	Ge, Hui [EL] Πίσπας, Στέργιος[EN] Pispas, Stergios Wu, Chi
Εκδότης:	Royal Society Chemistry
Τόπος έκδοσης:	Cambridge
Ημερομηνία:	2011
Γλώσσα:	Αγγλικά
ISSN:	1759-9954
DOI:	10.1039/c0py00361a
Περίληψη:	The ultrafiltration of star-like polystyrene chains with different arm lengths (L(A)) and arm numbers (f) passing through a nanopore (20 nm) under an elongational flow field was investigated in terms of the flow-rate dependent relative retention ((C(0) - C)/C(0)), where C(0) and C are the polymer concentrations before and after the ultrafiltration. Our results reveal that for a given L(A), the critical flow rate (q(c,star)), below which star chains are blocked, dramatically increases with f; but for a given f, is nearly independent on L(A), contradictory to the previous prediction made by de Gennes and Brochard-Wyart. We have revised their theory in the region f(in) < f(out), where f(in) and f(out) are the numbers of arms inside and outside the pore, respectively; and also accounted for the effective length of each blob. In the revision, we show that q(c,star) is indeed independent of L(A) but related to both f and f(in) in two different ways, depending on whether f(in) <= f/2 or >= f/2. A comparison of our experimental and calculated results reveals that most star chains pass through the nanopores with f(in) similar to f/2. Further study of the temperature dependent (C(0) - C)/C(0) of polystyrene in cyclohexane shows that there exists a minimum of q(c,star) at similar to 38 degrees C, close to the theta temperature of polystyrene star chains.
Τίτλος πηγής δημοσίευσης:	Polymer Chemistry
Τόμος/Κεφάλαιο:	2
Τεύχος:	5
Σελίδες:	1071-1076
Λέξεις-Κλειδιά:	Polymer Science
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© ROYAL SOC CHEMISTRY
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο