Nanomechanical properties of solvent cast polystyrene and poly(methyl methacrylate) polymer blends and self-assembled block copolymers

Abstract

Abstract. The nanomechanical properties of solvent-cast polymer thin films have been investigated using PeakForce™ Quantitative Nanomechanical Mapping. The samples consisted of films of polystyrene (PS) and poly(methyl methacrylate) (PMMA) obtained after the dewetting of toluene solution on a polymeric brush layer. Additionally, we have probed the mechanical properties of poly(styrene-b-methyl methacrylate) block copolymers (BCP) as randomly oriented thin films. The probed films have a critical thickness <50 nm and present features to be resolved <42 nm. The Young's modulus values obtained through several nanoindentation experiments present a good agreement with previous literature, suggesting that the PeakForce™ technique could be crucial for BCP investigations, e.g., as a predictor of the mechanical stability of the different phases.

Grain-Boundary-Induced Alignment of Block Copolymer Thin Films

“…The surface energy of PMMA (with respect to the air) is slightly higher than of PS [43], which justifies that the PMMA droplet is inside the PS droplet and not vice versa. A similar behavior has been presented before for the investigation of chemical guiding patterns [42,44].…”

“…The analysis of the wetting behavior of a homopolymer blend consisting of the components of the block copolymer can serve as a qualitative test for the surface energy in micrometric areas [26,42]. Here, we use this technique to qualitatively understand the surface energy by observing the behavior of a PS/PMMA blend in the modified and in the non-modified area.…”

Sequential Infiltration of Self-Assembled Block Copolymers: A Study by Atomic Force Microscopy

“…The applied force set points ranged between 10 and 25 nN; in particular, the force set point was adjusted to obtain optimal deformation for a reliable fit (1–2 nm) and not to produce plastic deformation . Further details about the experimental procedure for the imaging of BCP thin films are well described in refs and . During measurements in PeakForce Tapping mode, the tip oscillates at 2 kHz.…”

Assembly of miscible supramolecular network blends using DDA·AAD hydrogen-bonding interactions of pendent side-chains

“…However, moduli of polymer thin films as measured by various nanoindentation techniques can vary depending upon temperature, load, film thickness and contact model used. [63][64][65] The thickness of the PMMA/PS film was 125 nm, comfortably above the critical film thickness of approximately 50 nm, below which the measured modulus would substantially increase. 65 All other parameters are identical, so comparison of moduli values between samples is valid.…”

“…[63][64][65] The thickness of the PMMA/PS film was 125 nm, comfortably above the critical film thickness of approximately 50 nm, below which the measured modulus would substantially increase. 65 All other parameters are identical, so comparison of moduli values between samples is valid. Typical literature values found by nanoindentation on similarly prepared samples are for PMMA = 3.3 ± 0.5 GPa/PS = 2.6 ± 0.2 GPa, 65 PMMA = 4.1 GPa/PS = 3.0 GPa, 64 and PMMA = 5.5 GPa/PS = 4.3 GPa, showing that PMMA has a modulus that is reproducibly 30% higher than PS.…”