A Robotic High-Throughput Grid-Search Platform for Mapping Phase Behavior in Triblock Copolymer–Homopolymer Blends

Authors

• Saroj Upreti, University of Southern Mississippi
• Lan Xu, Texas A&M University
• Md Moniruzzaman, University of Southern Mississippi
• Yunfei Wang, University of Southern Mississippi
• Kailash Adhikari, University of Southern Mississippi
• Sabin Baral, University of Southern Mississippi
• Derek Patton, University of Southern Mississippi
• Boran Ma, University of Southern Mississippi
• Jie Xu, Argonne National Laboratory
• Ruipeng Li, Brookhaven National Laboratory
• Chenhui Zhu, Advanced Light Source, Berkeley
• Wenjie Xia, Texas A&M University
• Xiaodan Gu, University of Southern MississippiFollow

Document Type

Article

Publication Date

6-23-2026

Abstract

We present a high-throughput experimental investigation of the phase behavior in triblock copolymers (PS-b-PB-b-PS and PS-b-PI-b-PS) and polystyrene (PS) homopolymer blends as a function of homopolymer molecular weight (MW) and blend ratio. Using a robotic thin-film processing platform (NOVA) integrated with Grazing Incidence Small-Angle X-ray Scattering (GISAXS) and Atomic Force Microscopy (AFM), we systematically mapped the order–disorder transition (ODT) boundaries and domain spacing evolution across a broad MW range (4.0–101.3 kDa) with varying homopolymer loadings (10% to 90%). The results reveal three distinct regimes: low-MW homopolymers, corresponding to the wet-brush regime produced only gradual domain swelling before disordering at high blend ratios (weight fraction); medium-MW homopolymers, corresponding to thedry-brush regime induced significant domain spacing increase up to 80% followed by earlier disordering, while high-MW homopolymers led to macrophase separation with minimal changes in domain spacing. Additionally, coarse-grained molecular dynamics simulations confirmed our experimental finding that in the low-MW region, the PS homopolymer uniformly distributed in the PS domain. These findings demonstrate that homopolymer molecular weight critically governs both the extent of domain swelling and the onset of disorder in triblock copolymer systems. This high-throughput platform enables the rapid mapping of composition–morphology relationships and can be integrated with AI/ML tools for designing next-generation nanostructured polymers.

Publication Title

ACS Nano

Volume

20

Issue

24

First Page

17303

Last Page

17315

Recommended Citation

Upreti, S., Xu, L., Moniruzzaman, M., Wang, Y., Adhikari, K., Baral, S., Patton, D., Ma, B., Xu, J., Li, R., Zhu, C., Xia, W., Gu, X. (2026). A Robotic High-Throughput Grid-Search Platform for Mapping Phase Behavior in Triblock Copolymer–Homopolymer Blends. ACS Nano, 20(24), 17303-17315.
Available at: https://aquila.usm.edu/fac_pubs/22127