Defect evolution in ultrathin films of polystyrene-block-polymethylmethacrylate diblock copolymers observed by atomic force microscopy

1998 ◽  
Vol 109 (23) ◽  
pp. 10111-10114 ◽  
Author(s):  
J. Hahm ◽  
W. A. Lopes ◽  
H. M. Jaeger ◽  
S. J. Sibener
2005 ◽  
Vol 123 (4) ◽  
pp. 044706 ◽  
Author(s):  
J. M. K. Donev ◽  
Q. Yu ◽  
B. R. Long ◽  
R. K. Bollinger ◽  
S. C. Fain

Langmuir ◽  
2013 ◽  
Vol 29 (7) ◽  
pp. 2339-2349 ◽  
Author(s):  
Michail Kalloudis ◽  
Emmanouil Glynos ◽  
Stergios Pispas ◽  
John Walker ◽  
Vasileios Koutsos

2017 ◽  
Vol 32 (S1) ◽  
pp. S141-S150
Author(s):  
Dieter Jehnichen ◽  
Doris Pospiech ◽  
Peter Friedel ◽  
Andriy Horechyy ◽  
Andreas Korwitz ◽  
...  

This study investigates the morphology changes in thin diblock copolymer (DiBCP) films occurring in the interaction with modified nanoparticles (NPs). Magnetite (Fe3O4) and silica (SiOx) were prepared and used. Poly(pentyl methacrylate-b-methyl methacrylate) (PPMA-b-PMMA) (70/30 mol mol−1, hcp cylinders of the PMMA phase) DiBCP were employed to prepare thin films having thicknesses to realize standing cylinders in pure DiBCP films. The investigations aimed at two topics: (1) morphology after controlled incorporation of organo-modified NP (gold, silver, Fe3O4, SiOx) and (2) additional solvent vapour annealing (SVA) with tetrahydrofuran (and chloroform for comparison). The laterally ordered morphology in thin films was examined by GISAXS and atomic force microscopy. Keeping the same type of morphology in nanocomposites, the dimensions of the periodic nanostructure altered depending on type and amount of incorporated NP. It was found that SiOx clusters enlarge the lateral distance of the PMMA cylinders, whereas metallic NPs reduce this parameter. Applying SVA improves the phase separation slightly, whereas lateral distances were kept constant or were reduced a little. Switching of domain orientation upon SVA could not be detected in the presence of NPs located at the polymer/substrate interface.


2016 ◽  
Vol 89 (3) ◽  
pp. 392-405 ◽  
Author(s):  
C. A. Da Silva ◽  
M. Weydert ◽  
H. Budde ◽  
U. Wendler ◽  
M. Menzel ◽  
...  

ABSTRACT Two series of poly(butadiene-block-(styrene-stat-butadiene) (PB-SBR) diblock copolymers were synthesized to study interrelations between microphase-separated state and relaxation dynamics. Series I consists of six symmetric PB-SBR samples (ΦSBR ∼ 0.50) with different styrene contents in the random SBR block (21 mol% ≤ xS,SBR ≤ 52 mol%). Series II contains six asymmetric PB-SBR diblock copolymers with almost constant styrene content in the SBR block (xS,SBR = 32 ± 4 mol%) and SBR volume fractions in the range of 0.20 ≤ ΦSBR ≤ 0.69. All PB-SBR diblock copolymers have a total molecular weight of about 200 kg/mol with 1,2-vinyl content of about 8.5 and 15.8 mol% in the soft PB and in the hard SBR block, respectively. A novel synthesis route has been developed so as to maintain low 1,2-vinyl contents in both blocks and a random distribution of the styrene units in the SBR block. The softening behavior of non–cross-linked PB-SBR diblocks was investigated by differential scanning calorimetry, providing first information about miscibility. The morphology of cross-linked PB-SBR diblock copolymers, which have been vulcanized with sulfur at 150 °C using standard procedures, was studied by atomic force microscopy. Dynamic shear measurements aimed at understanding the influence of morphological changes on the segmental dynamics of both phases, αPB and αSBR, were performed on vulcanized samples. Atomic force microscopy results and shear data indicate that symmetric diblock copolymers with styrene content higher than 27 mol% in the SBR block are well microphase separated. Strongly segregated states are also observed for asymmetric diblock copolymers with volume fractions 0.28 ≤ ΦSBR ≤ 0.60 showing cylindrical and lamellar morphologies. The origin of changes in the αPB and αSBR dynamics depending on morphology and segregation strengths is considered. Implications for the use of rubbery PB-SBR block copolymers in composites for tire treads are discussed.


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