Elastic property of membranes self-assembled from diblock and triblock copolymers

• Published in: Chemistry and physics of lipids 2019-07, Vol.221, p.83-92
• Main Authors: Xu, Rui, Dehghan, Ashkan, Shi, An-Chang, Zhou, Jiajia
• Format: Article
• Language: English
• Subjects: Bolalipids; Hydrophobic and Hydrophilic Interactions; Lipid Bilayers - chemical synthesis; Lipid Bilayers - chemistry; Lipids - chemistry; Membrane; Polymers - chemistry; Self-consistent field theory
• ISSN: 0009-3084; 1873-2941
• DOI: 10.1016/j.chemphyslip.2019.03.015

•ABA triblock membrane is studied as a coarse-grained model of bolalipids.•The elastic properties of ABA triblock membrane is calculated using self-consistent field theory.•Comparison between ABA triblock membrane and AB diblock membrane sheds light on the effects of molecular topology. The elastic property of membranes self-assembled from AB diblock and ABA triblock copolymers, as coarse-grained model of lipids and the bolalipids, are studied using the self-consistent field theory (SCFT). Specifically, solutions of the SCFT equations, corresponding to membranes in different geometries (planar, cylindrical, spherical, and pore) have been obtained for a model system composed of amphiphilic AB diblock copolymers and ABA triblock copolymers dissolved in A homopolymers. The free energy of the membranes with different geometries is then used to extract the bending modulus, Gaussian modulus, and line tension of the membranes. The results reveal that the bending modulus of the triblock membrane is greater than that of the diblock membrane. Furthermore, the Gaussian modulus and line tension of the triblock membrane indicate that the triblock membranes have higher pore formation energy than that of the diblock membranes. The equilibrium bridging and looping fractions of the triblock copolymers are also obtained. Implications of the theoretical results on the elastic properties of biologically equivalent lipid bilayers and the bolalipid membranes are discussed.