Real-time andin situobservation of structural evolution of giant block copolymer thin film under solvent vapor annealing by atomic force microscopy

Abstract

An instrumentation technique for real-time, in situ and real space observation of microphase separation was proposed for ultra-high molecular weight block copolymer thin films (1010 kg mol À1 , domain spacing of 180 nm) under high solvent vapor swelling conditions. This is made possible by a combination of a homebuilt chamber which is capable of supplying sufficient amount of vapor, and force-distance curve measurements which gives real-time swollen film thickness and allow active feedback for controlling the degree of swelling. We succeeded in monitoring the domain coarsening of perpendicular lamellar structures in polystyrene-block-poly(methyl methacrylate) thin films for eight hours via tapping mode imaging. During the annealing process, the thickness reached a maximum of 8.5 times that of the original film. The series of temporal real space topographic images obtained via this method allowed us to study, for the first time, the growth exponent of the correlation length under solvent vapor annealing. † Electronic supplementary information (ESI) available: Solvent vapor annealing using reectometry, selective swelling of PS and PMMA homopolymers in THF, USAXS measurement of bulk BCP phase-separated pellets, defect analysis of AFM topographic images, and morphology assignment by SEM. See

Correlating polymer structure, dynamics, and function with atomic force microscopy

“…Takano et al recently demonstrated in situ AFM imaging within a sealed SVA chamber, enabling direct measurements of solvent‐swollen films. The system monitored the coarsening of fingerprint patterns in ultrahigh molecular weight PS‐b‐PMMA thin films over an 8 h period of in situ SVA imaging, shown in Figure 5 103 . DIA offers a method to overcome many of the challenges associated with SVA, fully immersing BCP films in a tunable solvent mixture, in order to maintain a finite interaction parameter for microphase separation 104,105 …”

“…The system monitored the coarsening of fingerprint patterns in ultrahigh molecular weight PS-b-PMMA thin films over an 8 h period of in situ SVA imaging, shown in Figure 5. 103 DIA offers a method to overcome many of the challenges associated with SVA, fully immersing BCP films in a tunable solvent mixture, in order to maintain a finite interaction parameter for microphase separation. 104,105 AFM imaging has been extensively used to study the dynamics and mechanisms of BCP defect healing and grain coarsening during thermal annealing.…”

“…Over the 8.0 h annealing time, the polymer domains coarsened and correlation length increased, while defect density decreased. Adapted under Creative Commons from Reference 103. Published by the Royal Society of Chemistry [Color figure can be viewed at wileyonlinelibrary.com]…”

Microphase separation/crosslinking competition-based ternary microstructure evolution of poly(ether-b-amide)

“…Due to the thermodynamic immiscibility between the segments, several long-range order structures can be formed within a sub-micrometer scale (known as microphase separation). [1][2][3][4][5] With extensive research, the morphology of different phases is greatly affected by the Flory interaction parameters between the two segments, composition, and the overall degree of polymerization. [6][7][8][9][10][11][12][13][14] Furthermore, the material properties such as modulus, [15][16][17] conductivity, 18,19 and rheological properties 20,21 can be enhanced at the order states.…”

Strategy for Enhancing Ultrahigh-Molecular-Weight Block Copolymer Chain Mobility to Access Large Period Sizes (>100 nm)

“…Lastly, in 2020, Hayashi and co-workers reported the real time self-assembly observation of an UHMW PS-b-PMMA (Mw = 1010 kg mol -1 ). 28 While ≈ 180 nm period lamellar features were achieved, very long solvent vapor annealing times (6 to 8 hrs) were required, which is problematic from a fabrication standpoint. Others have also demonstrated large period cylindrical patterns; 29,30 however, robust routes that use compatible solvents and truly rapid deposition methods do not exist for assembling UHMW BCPs.…”