Session C1: Poster Session I (2:00-5:00PM)

2:00 PM–2:00 PM, Monday, February 27, 2012
Room: Exhibit Hall C

Abstract ID: BAPS.2012.MAR.C1.181

Abstract: C1.00181 : Phase Behavior of Hydrogenated Derivatives of Linear ABC Block-Random Copolymers of Styrene and Isoprene

Preview Abstract   MathJax On | Off     Abstract  


  Bryan Beckingham
    (Princeton University)

  Richard Register
    (Princeton University)

The capacity to synthesize block-random copolymers, block copolymers with one or more random copolymer blocks, allows for continuous tuning of the inter-block average segmental interaction parameter, $\chi $, through the composition of the random copolymer without changes to system chemistry. By lithium-initiated anionic polymerization in a mixture of cyclohexane and triethylamine, we synthesized an asymmetric near-monodisperse linear ABC block-random copolymer of styrene and isoprene: S$_{30}$-I$_{12}$-SrI$_{12}$, where SrI denotes a random copolymer block with 50 wt. {\%} styrene, and block molecular weights are 30-12-12 kg/mol. Upon complete hydrogenation, the VCH-hI-VCHrhI triblock exhibits microphase separation into a well-ordered two-domain lamellar structure with an order-disorder transition between 180-185\r{ }C via small-angle x-ray scattering. This two-domain lamellar structure is confirmed using electron density modeling of the SAXS peak intensity and domain spacing arguments. A three-domain lamellar structure is expected in the diene-selective hydrogenated derivative, S-hI-SrhI, due to increased $\chi $ between the middle and end blocks. Additional S-I-SrI and S-SrI-I triblock copolymers are being synthesized and the effects of block sequence, end block molecular weight, and hydrogenation (S vs. VCH) on phase behavior are being explored.

To cite this abstract, use the following reference: