Improved self‐assembly of poly(dimethylsiloxane‐b‐ethylene oxide) using a hydrogen‐bonding additive |
| |
| Authors: | Damien Montarnal Zoltan Mester Christian W. Pester Alaina J. McGrath Glake Hill Glenn H. Fredrickson Craig J. Hawker |
| |
| Affiliation: | 1. Materials Research Laboratory, University of California, Santa Barbara, California;2. Laboratoire de Chimie Catalyse Polymères et Procédés (C2P2), Université de Lyon 1, CPE Lyon, CNRS, UMR 5265, Villeurbanne, France;3. Department of Chemical and Biological Engineering, Princeton University, New Jersey;4. Department of Chemistry and Biochemistry, Jackson State University, Jackson, Mississippi;5. Materials Department, University of California, Santa Barbara, California;6. Department of Chemical Engineering, University of California, Santa Barbara, California;7. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California |
| |
| Abstract: | Block copolymers with increased Flory–Huggins interaction parameters (χ) play an essential role in the production of sub‐10 nm nanopatterns in the growing field of directed self‐assembly for next generation lithographic applications. A library of PDMS‐b‐PEO block copolymers were synthesized by click chemistry and their interaction parameters (χ) determined. The highest χ measured in our samples was 0.21 at 150 °C, which resulted in phase‐separated domains with periods as small as 7.9 nm, suggesting that PDMS‐b‐PEO is a prime candidate for sub‐10 nm nanopatterning. To suppress PEO crystallization, PDMS‐b‐PEO was blended with (l )‐tartaric acid (LTA) which allows for tuning of the self‐assembled morphologies. Additionally, it was observed that the order‐disorder transition temperature (TODT) of PDMS‐b‐PEO increased dramatically as the amount of LTA in the blend increased, allowing for further control over self‐assembly. To understand the mechanism of this phenomenon, we present a novel field‐based supramolecular model, which describes the formation of copolymer‐additive complexes by reversible hydrogen bonding. The mean‐field phase separation behavior of the model was calculated using the random phase approximation (RPA). The RPA analysis reproduces behavior consistent with an increase of the effective χ in the PDMS‐b‐(PEO/LTA suprablock). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2200–2208 |
| |
| Keywords: | block copolymer lithography click chemistry polymer blend supramolecular assembly phase separation |
|
|
