Synthesise And Self-Assembly Of Helical Amphiphilic Graftcopolymer With MPEG

People have interest in helical polymer due to ubiquitous nature helix structure. While only nature helical polymers self-assemble into high-level organizational structures and can play important roles in human life. Therefore, further study in the self-assembly of helical polymer is particularly important. In this paper, novel amphiphilic graftcopolymers were synthesized, and the self-assembly behavior of copolymers was studied. Detailed works were described as follows:1. The novel graftcopolymers of polyacetylene—MPEG (polyethylene glycol monomethyl ether) having C-chirality and hydrophilic macromolecule as pendant groups were synthesized via (nbd)Rh+[η6-C6H5B-(C6H5)3] as catalyst. The structure of copolymers was characterized by FT-IR. Moderate molecular weights (Mn) (13000-15000) and Mw/Mn (2.1-2.2) of copolymers were measured by GPC.2. The optical activity and secondary structure of the copolymers were characterized by specific rotations ([α]D) and circular dichroism (CD) spectra. Five factors(Mn of MPEQ amount of MPEQ methanol content, polarity of solvents, time) were observed to affect the helix structure of polymers. The results showed that the copolymers had optical activity and could form single helical conformation. The optical activitiy of copolymers decreased gradually as the Mn and amount of MPEG increased, also decreased as the time delayed and the methanol content increased. The helical conformation of the copolymers kept the better stability in CHCl3 comparing to other three selective solvents (THF, CH2C12, benzene).3. The assembly phenomenon of the poly(la80-co-3b20) was studied in different solvents systems(dioxane/H2O, CHCl3/H2O, THF/H2O) with different concentrations(initial concentration:1 mg·mL-1, 0.2mg·mL-1). By the SEM images of these systems, we could get conclusion that the copolymer could self-assemble into some orderly congeries in relatively dilute solvent-systems under the synergy effect of internal hydrogen bond-driven and external hydrophilic/hydrophobic-driven, while it is difficult to form orderly congeries in relatively dilute solvent-systems.