1 and f B ≥ 0.7 and the compositions f A = 0.3, f B = 0.3, f C = 0.4, and f A = 0.4, f B = 0.3, f C = 0.3. b. Selleck 10058-F4 Influence of the grafting density We also consider the grafting density σ = 0.15 when χ AB N = χ BC N = χ AC N = 35. The grafting density decreases a little, which shows that the effective film thickness increases. The phase diagram is shown in Figure click here 3. From the figure, we can see that the lamellar phase region contracts and some new phases emerge, such as two-color perpendicular lamellar phase (LAM2 ⊥) and core-shell hexagonally packed spherical phase (CSHS). Due to the decrease of the grafting density, the influence of the brush will
weaken. Similar with the case of σ = 0.20, the core-shell structures occur near the corners A and C. CSHS phase forms at f A = 0.10, f B = 0.10, f C = 0.80; f A = 0.80, f B = 0.10, f C = 0.10. The core-shell cylindrical
phase occurs near the phase CSHS. In these cases, the block A (or C) forms the majority, the block C (or A) forms the ‘core,’ and the middle block B is around the block C (or A) forming the ‘shell’ of the core. Figure 3 Phase diagram of ABC triblock copolymer with χ AB N = χ BC N = χ AC N = 35 at grafting density σ = 0.15. Dis represents the disordered phase. Comparing the phase diagram with that in the bulk , the www.selleckchem.com/products/Flavopiridol.html direction of the lamellar phase can be tailored by changing the grafting density when the middle blocks are the minority and the ABC triblock Ibrutinib purchase copolymer
is symmetric, i.e. f A = f C. The parallel lamellar phase with hexagonally packed pores at surfaces (LAM3 ll -HFs) can easily form at some compositions. In general, the block copolymer experiences the film confinement under this condition. Moreover, the block copolymer experiences the brush polymer tailoring, especially at the interface between the block copolymer and the polymer brush. Therefore, some new phases form, and the phase diagram is more complicated. Even for the lamellar phase, there are two styles: the perpendicular and parallel ones. The perpendicular lamellar phase always occurs when the volume fractions of the three components are comparable. The parallel lamellar phase forms at the middle edge of the phase diagram in most cases. From the above two phase diagrams, we can see that the hexagonally packed pores at the interface between the block copolymers and the polymer brush-coated surfaces occur. It is very useful in designing thin films with functional dots. 2. Frustrated case χ AB N = χ BC N = 35, χ AC N = 13 It is energetically unfavorable when χ AC N < < χ AB N ≈ χ BC N; that is to say, the repulsive interaction between the two ends is the smallest in the three interaction parameters. Thus, the block B has to be limited in spheres, rings, or cylinders to increase the contacting interface between the blocks A and C.