title: Prediction and observation of sustained oscillations in a sheared liquid crystalline polymer.
abstract: Experimental observations of sustained oscillations of both shear stress and first normal stress differences are reported in flowing liquid crystalline polymers in a limited range of shear rates. The results can be described by considering the response of a rigid-rod model. Depending on the initial conditions, the frequency spectrum of the stress signal contains either one or two characteristic frequencies. This can be explained by the occurrence of either pure "wagging" or the coexistence of wagging and "log-rolling" behavior of the director.
authors.affiliation: Dipartimento di Ingegneria Chimica, Universitá Federico II di Napoli, Piazzale Tecchio 80, I-80125, Napoli, Italia.
authors.forename: M
authors.initials: M
authors.lastname: Grosso
authors.forename: S
authors.initials: S
authors.lastname: Crescitelli
authors.forename: E
authors.initials: E
authors.lastname: Somma
authors.forename: J
authors.initials: J
authors.lastname: Vermant
authors.forename: P
authors.initials: P
authors.lastname: Moldenaers
authors.forename: P L
authors.initials: PL
authors.lastname: Maffettone
mesh_terms: D003408:Cresols / Q000737:chemistry; D008956:Models, Chemical; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013314:Stress, Mechanical
chemical_list: D003408:Cresols; D011108:Polymers; C003172:poly-gamma-benzyl-L-glutamate; D011099:Polyglutamic Acid; C077977:cresol