Abstract

The use of short chain block copolymer melts as nanostructured templates with sub-10 nm domains is often limited by their low segregation strength (χN). Since increasing molar mass to strengthen segregation also increases the interdomain spacing of block copolymer melts, it is more desirable to increase the Flory−Huggins segment−segment interaction parameter, χ, to produce strong segregation. We have recently shown that poly(oxyethylene−oxypropylene−oxyethylene) block copolymer melts can undergo disorder-to-order transition when blended with a selectively associating homopolymer that can hydrogen bond with one of the blocks. Here, we study the effect of the molar mass of poly(acrylic acid) in the range 1−13 times that of the copolymer on the segregation of a 6.5 kg/mol poly(oxyethylene−oxypropylene−oxyethylene) copolymer melt. The neat copolymer is disordered, and the addition of poly(acrylic acid) resulted in a well-ordered lamellar morphology with an interdomain spacing of 10 ± 1.0 nm. Using small-angle and ultrasmall-angle X-ray scattering, we found that the blends remain well ordered at 80 °C over the entire range of homopolymer chain lengths. A small increase in the interdomain spacing of the lamellae and an order−order transition from lamellae-to-cylindrical morphology was observed in all blends as a function of increasing homopolymer concentration. The trends observed in experiments were validated by self-consistent field theoretical simulations.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.