Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers.

Jeffery Gaspard,Dany J Munoz-Pinto,Mariah S Hahn,James A Silas,Matt Rozin,Liam M Casey

doi:10.3390/s16030390

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.

Highlights

Block copolymer-based vesicles have been instrumental in developing mechanically robust nano/micron-scale reactors, drug carriers, and sensors [1,2,3,4,5,6,7,8,9]
A 5 mg/mL solution of each block copolymer mixture was prepared in DCM, a solvent which is able to effectively solubilize both PDMS-PEO and PBd-PEO
The present manuscript investigates the high tension mechanical behavior of vesicles formed from graded mixtures of linear PDMS12 -PEO42 and PBd33 -PEO20 as a first step toward the long-term goal of enabling broad, application-specific tailoring of polymersome membrane fluidity and permeability

Summary

Introduction

Block copolymer-based vesicles have been instrumental in developing mechanically robust nano/micron-scale reactors, drug carriers, and sensors [1,2,3,4,5,6,7,8,9]. Toward this end, end,wewe chose to generate frompoly(butadiene(1-2 linear poly(butadiene(1-2. End,wewe chose to generate frompoly(butadiene(1-2 linear poly(butadiene(1-2 Toward this chose to generate hybridhybrid vesiclesvesicles from linear addition)addition)-b-ethylene oxide) (PBd-PEO) (Figure 1A) [9,10,11,12,13,14,15,16,17]. Linear poly(dimethylsiloxane-b-ethylene b-ethylene oxide) (PBd-PEO) (Figure 1A) [9,10,11,12,13,14,15,16,17] and linear poly(dimethylsiloxane-b-ethylene oxide) oxide) (PDMS-PEO)

Methods

Results

Conclusion