Suppression of Filler Disrupting Morphology in Nanofilled

Block Copolymer Films with Cold Zone Annealing (CZA)

Alamgir Karim, University of Akron, DMR 1006421

Nanoparticles can modified functionality of polymer films by virtue of their optical, electrical, thermal, dielectric properties that uniquely depend on their nanoscale dimensions. Block copolymer (BCP) films organize into periodic nanostructures to behave much like a crystal with important nanotechnology applications such as membranes for water-oil separation, data storage, optical wave-guides, etc. However, as shown in (a), immobile silica nanoparticles can disrupt the PS-PMMA BCP morphology leading to “target patterns” around them with loss of the BCP film structure and properties.

We examine the effect of a moving in-plane temperature gradient on the ordering of cylinder-forming block-copolymers (BCP) in films containing immobilized nanoparticles that span the film thickness. In the dynamic film annealing method of the present work, termed cold zone annealing (CZA), the material is continuously raised to a temperature above the glass transition temperature with control of thermal gradient.

CZA is found to eliminate large-scale BCP “target patterns” induced by wetting and stresses associated with residual solvent and thermal expansion. CZA naturally suppresses undesirable target patterning (b), with enhanced ordering kinetics and aligns BCP morphology, similar to unfilled BCP films (c).

Left panel: AFM images of a) Oven annealed BCP with nanoparticles vs. b) CZA BCP morphology. Right panel: Corresponding BCP orientation homogeneity color map. Zhang et al., Soft Matter, 2014, 10, 3656

St. Vincent St. Mary High School (STVM) Outreach: St. Vincent St. Mary High School student Joseph (Joe) Puhalla continued research through Spring 2014 in the joint program between University of Akron’s College of Polymer Science and Polymer Engineering (CPSPE), leveraged by Prof. Karim’s NSF-DMR funded project. Joe’s research involved effects of dynamic thermal annealing on block copolymer stratification. Joe participated in various science fairs:At STVM Science Fair 2014, Joe was 3rd Place in Physics, Engineering and Computers Category; at the 1st North East Ohio Science and Engineering Fair, Joe came 2nd, and won 4 special awards from: ASM Materials Education, ASM International, Society of Plastics Engineers, and the Yale Science and Engineering award. In addition at the district fair, Joe qualified for the State Science fair in Columbus.

Western Reserve Academy (WRA) Summer Outreach (New 2014): In a new pilot program initiative, a joint research summer program between CPSPE and WRA High School for summer of 2014 was established. A total of 6 students was selected by WRA and matched with their research interests to faculty advisors at CPSPE. The students spent the summer doing research in faculty laboratories with graduate students up to four days a week. The project, also leveraged by the NSF-DMR outreach thrust, will be repeated in summer of 2015.

Joe Puhalla worked on block copolymer thin film stratification.

Michael Zeleznik (left) of Western Reserve Academy in Hudson, Ohio worked on kinetics of block copolymer thin film ordering with graduate student Arvind Modi (right).

Suppression of Filler Disrupting Morphology in Nanofilled

Block Copolymer Films with Cold Zone Annealing (CZA)

Alamgir Karim, University of Akron, DMR 1006421