Synthesis Of Diblock Copolymer And Preparation Of Ordered Nano Thin Film

In this paper, the self-assembly behavior of ordered diblock copolymerthin film was investigated. Poly(ethylene oxide)-b-polystyrene(PEO-b-PS) andpolystrene-b-polymethyl-methacrylate diblock copolymer(PS-b-PMMA) weresynthesized by Atom transfer radical polymerization(ATRP). Forself-assembly of PS-b-PMMA, the effects of solvent evaporation treatment onthe morphology of copolymer thin film was studied. For self-assembly ofPEO-b-PS, thin film was obtained via spin-coating and dip-coating. Theeffects of spin-coated environment and solvent evaporation treatment on themorphology of PEO-b-PS with different molecular weight thin film wasinvestigated. The self-assembly of PEO-b-PS and its complex system werefurther studied. The main contents had the following four aspects:1. PS-b-PMMA and PEO-b-PS wth two different molecular weight wereprepared by ATRP. The molecular weight and the molecular distributionweight of PS-b-PMMA were32800and1.37. The molecular weight of twotypes of PEO-b-PS were37000and29900while the molecular distributionweight were1.25and1.22respectively. In these experiments, diblockcopolymer with narrow molecular weight distribution and controllable weight fraction diblock were synthesized successfully.2.0.4wt%and0.6wt%PS-b-PMMA/THF solution were spin-coated intothin films. With the time of CHCl3solvent evaporating treatment to the thinfilms increased, cylindrical swelling of PMMA were formed gradually.Cylindrical swelling turned into collapse with the trend of two swellingsolvating with each other in a certain period of evaporating treatment time.Theamount of cylindrical swelling increased and formed ordered films.3. In the system of PEO-b-PS spin-coating film, PEO-b-PS-1/benzenesolutions were spin-coated into obviously phase seperated film via solventevaporation environment compared with the film which was formed in naturalenvironment; Films which were spin-coated in toluene/water evaporation bytwo PEO-b-PS-1(12.9wt%)/toluene solution with different concentration andtreated by solvent evaporation, the morphology of copolymer thin films werePEO cylinder distribution in PS matrix. Long-range ordered、hexagon cylinderpacked films formed by spin-coating via toluene/water evaporation and treatedwith co-solvent after that; After adding PEO-OH homopolymer to the system,the dimensions of PEO diblock cylinder was controllable because of thereaction between PEO-OH homopolymer and PEO diblock.4. In the system of PEO-b-PS dip-coating film, changing dip-coatingenvironment, the morphology of0.5wt%PEO-b-PS-1(PEO=12.9wt%)/toluenedip-coated film was strips、irregular cylinder、opposite cylinder and orderednano cylinder; The size of PEO diblock cylinder in dip-coating films using 0.5wt%PEO-b-PS-1(PEO=12.9wt%)/toluene&water was increased because ofthe hydrophilicity of PEO; With the amount of paranitroaniline increasing to0、0.05wt%、0.1wt%and0.3wt%, the morphology of0.5wt%PEO-b-PS-2(PEO=15.5wt%)/CHCl3dip-coating films was cylinder-like、multi-layer andcylinder-like through the hydrogen bonding interaction. Addingmdinitrobenzene to0.5wt%PEO-b-PS-2(PEO=15.5wt%)/CHCl3solution,the morphology of these films were disordered. This result was indirect prooffor the existence of hydrogen bonding interaction in0.5wt%PEO-b-PS-2(PEO=15.5wt%)/CHCl3&mdinitrobenzene dip-coating films.