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Title: Nonlinear chiral rheology of phospholipid monolayers
Microbutton rheometry reveals that the chiral morphology of dipalmitoylphosphatidylcholine (DPPC) monolayers imparts a chiral nonlinear rheological response. The nonlinear elastic modulus and yield stress of DPPC monolayers are greater when sheared clockwise (C), against the natural winding direction of DPPC domains, than counter-clockwise (CC). Under strong CC shear strains, domains deform plastically; by contrast, domains appear to fracture under strong C shearing. After CC shearing, extended LC domains develop regular patterns of new invaginations as they recoil, which we hypothesize reflect the nucleation and growth of new defect lines across which the tilt direction undergoes a step change in orientation. The regular spacing of these twist-gradient defects is likely set by a competition between the molecular chirality and the correlation length of the DPPC lattice. The macroscopic mechanical consequences of DPPC's underlying molecular chirality are remarkable, given the single-component, non-cross-linked nature of the monolayers they form.  more » « less
Award ID(s):
1706378
PAR ID:
10057718
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
Soft Matter
Volume:
14
Issue:
13
ISSN:
1744-683X
Page Range / eLocation ID:
2476 to 2483
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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