title: Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers.
abstract: Poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO) and poly(butadiene-b-ethylene oxide) (PBd-PEO) are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness of the resulting hybrid vesicles must first be confirmed. Toward this end, we have characterized the mechanical behavior of vesicles formed from mixtures of linear PDMS-PEO and linear PBd-PEO using micropipette aspiration. Tension versus strain plots of pure PDMS12-PEO46 vesicles revealed a non-linear response in the high tension regime, in contrast to the approximately linear response of pure PBd33-PEO20 vesicles. Remarkably, the area expansion modulus, critical tension, and cohesive energy density of PDMS12-PEO46 vesicles were each significantly greater than for PBd33-PEO20 vesicles, although critical strain was not significantly different between these vesicle types. PDMS12-PEO46/PBd33-PEO20 hybrid vesicles generally displayed graded responses in between that of the pure component vesicles. Thus, the PDMS12-PEO46/PBd33-PEO20 hybrid vesicles retained or exceeded the strength and toughness characteristic of pure PBd-PEO vesicles, indicating that future assessment of the membrane permeability and fluidity of these hybrid vesicles may be warranted.
authors.affiliation: Department of Chemical Engineering, Texas A&amp;M University 3122 TAMU, College Station, 77840 TX, USA. jeffery.gaspard@hotmail.com.
authors.forename: Jeffery
authors.initials: J
authors.lastname: Gaspard
authors.affiliation: Department of Chemical Engineering, University of Massachusetts, Amherst, 01003 MA, USA. lmcasey@umich.edu.
authors.forename: Liam M
authors.initials: LM
authors.lastname: Casey
authors.affiliation: Department of Chemical Engineering, University of Massachusetts, Amherst, 01003 MA, USA. mrozin@ucsd.edu.
authors.forename: Matt
authors.initials: M
authors.lastname: Rozin
authors.affiliation: Engineering Science Department, Trinity University, San Antonio, 78212 TX, USA. dmunozpi@trinity.edu.
authors.forename: Dany J
authors.initials: DJ
authors.lastname: Munoz-Pinto
authors.affiliation: Department of Chemical Engineering, Texas A&amp;M University 3122 TAMU, College Station, 77840 TX, USA. james.a.silas@gmail.com.
authors.forename: James A
authors.initials: JA
authors.lastname: Silas
authors.affiliation: Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Biotech 2434, Troy, 12180 NY, USA. hahnm@rpi.edu.
authors.forename: Mariah S
authors.initials: MS
authors.lastname: Hahn
keywords: hybrid vesicles; poly(butadiene); poly(dimethylsiloxane); polymersomes