Time: 10:00 a.m., August 16, 2024 (Friday)

Location：Room 227, No.1 Laboratory Building, North District, China

Lecturer: Li Weihua

Abstract:The ordered arrangement (“crystallization”) of molecules confers a wealth of properties on the substances they constitute. For example, carbon atoms can be arranged into diamond or graphite structures, both of which have vastly different properties. When small molecules are polymerized into large molecules (polymers), it is difficult for them to “obey” as small molecules to arrange into large-scale ordered structures (crystallization), the fundamental reason is that their conformational entropy is “playing tricks”, which makes it difficult to be “straightened out”. The fundamental reason is that its conformational entropy is “playing tricks”, making it difficult to be “straightened”. So can we “command” the polymer to arrange into a large-scale ordered structure? Block copolymers are formed by different chemical compositions of polymers connected by covalent bonds, and their different blocks tend to “separate” due to chemical incompatibility, and “hand in hand” limits their separation, so they have to carry out periodic ordering arrangement Therefore, they have to be periodically ordered to form a mesoscopic scale ordered structure, which is the block copolymer self-assembly. “Self-assembly” is a spontaneous method of forming ordered structures, and this unparalleled method is also prevalent in nature. In this presentation, I will share with you that we have realized a variety of novel “mesoscopic crystal” structures based on self-consistent field-theoretic calculations and “targeted” design of block copolymer molecules. Fortunately, many of our theoretical predictions have been confirmed experimentally.