Diblock copolymer micelles film formation

Inorganic Modification and Film Formation of Diblock Copolymer Micelles... 

Circular surface micelles have also been observed for non-ionic block copolymers. Li et at. (1993) reported TEM and AFM of starfish micelles formed by PS-poly(n-butyl methacrylate), PS-poIy(rm-butyl methacrylate) and poly(fer<-butyl acrylate) diblock copolymers. Plateaus observed in surface/area isotherms of the Langmuir-Blodgett films at the air-water interface were consistent with the formation of surface micelles. 

Diblock copolymer poly(methyl methacrylate)-W0c -poly(2-hydroxyethyl methacrylate) PMMA- -PHEMA was used as the template for the self-assembly of palladium nanoparticles.98 Thin films of the metal-free block copolymer were obtained by dip coating from different solvents. The copolymer existed in the ordinary form and inverted micelles when it was dissolved in 1,4-dioxane and methanol, respectively. This was attributed to the hydrophilic properties of the PHEMA block. 2-Methoxyethanol, which is a common solvent to both blocks, was also used in the coating. Films obtained from 1,4-dioxane and methanol solutions showed the formation of spherical domains that were arranged in a 2-D hexagonal lattice, while the film obtained from 2-methoxyethanol showed a stripe pattern. Their AFM topography images are shown in Figure 5.19. The block copolymer thin films were then exposed to... 

A-B diblock copolymers can be used to form micelles that allow the preparation of thin, coherent films of well-developed stmcture [73-79]. For example, both poly (styrene)-block (fo)-poly(ethylene oxide) and poly(styrene)-b-poly(2-vinylpyridine) have been identified as useful combinations for generating well-ordered compartments in which metal nanoparticies can be fabricated in a variety of ways. The formation of diblock copolymers from polymer A and polymer B, ultimately producing nanospheres that can be transferred to films of highly ordered micelles, is illustrated in Figure 4.30a. The formation of metal nanoparticies inside the micelles is shown schematically in Figure 4.30b. 

Multiscale surface structures have been directly obtained by simple spin-coating from diblock copolymer/homopolymer blends. For instance. Park et al. [89] prepared films from PS-b-P2VP/PMMA blends. These films were prepared from a selective solvent either for PS or PMMA. The pure block copolymers (BCP) form nanometer-sized micelles as a consequence of the microphase separation due to the incompatibility between the constituent blocks (Fig. 6.13(a)). However, blending the BCP with a homopolymer induces macrophase separation between the BCP micelles and the PMMA and the formation of isolated PMMA micrometer-size domains (Fig. 6.13(b)-(e)). Other groups including Jeong et al. [50] or Ibarboure et al. [42] also used homopolymer/BCP blends to fabricate multiscale ordered surfaces. Jeong and coworkers used P(S-b-MMA)/PMMA blends with variable composition. 

Section 3 then reviews the behavior of diblock copolymers in mixed micelles with surfactants. Section 4 discusses other polymer surfactant mixtures, such as mixtures of amphiphilic poly(para-phenylenes) (PPP) with nonionic surfactants [48]. The packing parameter and the curvature of an amphiphilic BCP are not only influenced by means of co-micellization with a surfactant. Both parameters can also be influenced by changing the solvent quality for one of the blocks, e.g., by adding alcohol or salt. Denkova et al. have shown that this also leads to structural changes [49], However, despite the similarity of both approaches, the present review will only focus on aqueous BCP surfactant mixtures. Surfactants can also be used to assist structure formation in BCP thin films [50], This is an area of growing importance, but is beyond the scope of the present contribution. 

---