TY - JOUR
T1 - Reduced domain size and interfacial width in fast ordering nanofilled block copolymer films by direct immersion annealing
AU - Longanecker, Melanie
AU - Modi, Arvind
AU - Dobrynin, Andrey
AU - Kim, Seyong
AU - Yuan, Guangcui
AU - Jones, Ronald
AU - Satija, Sushil
AU - Bang, Joona
AU - Karim, Alamgir
N1 - Funding Information:
The block copolymer ordering study by neutron reflection was supported by the National Science Foundation (NSF) via Grant DMR- 1411046, while the nanoparticle incorporation aspects related to the potential for modifying film glassy behavior by nanoparticles was supported by the W.M. Keck Foundation. Joona Bang acknowledges the support by the Global Frontier R&D Program (No. 2013M3A6B1078869) on Center for Hybrid Interface Materials (HIM) funded by the Ministry of Science, ICT & Future Planning.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/11/22
Y1 - 2016/11/22
N2 - Block copolymers (BCPs) can function as nanoscale templates to organize nanoparticles within selective domains. Most functional applications of nanofilled BCPs generally require a high loading of nanoparticles, which is difficult to achieve due to particle aggregation, slow kinetics of ordering, and disruption of block copolymer order. A key parameter is the periodic domain spacing, L0, which is important for tuning functional properties. We demonstrate direct immersion annealing (DIA) as a promising directed self-assembly (DSA) method to overcome these problems. DIA is shown to fully order highly filled (10.5 vol % Au-PSrPMMA nanoparticles) lamellar poly(styrene-b-methyl methacrylate) (PS-PMMA) BCP films, whose lamellar ordering is practically unimpeded by filler loading. Neutron reflection (NR) further confirms that DIA sharpens the interfacial width between PS-PMMA domains by ∼20%. In situ NR studies further reveal that DIA predominantly induced film ordering in a 5 wt % anisotropic organoclay (C93A) filled PS-PMMA film in less than 30 s! In contrast, identical C93A nanofilled PS-PMMA films that were thermally annealed (19 h at 160 °C) only exhibit partial ordering near the free surface. DIA films also exhibit ∼50% reduced L0, resulting in twice the number of BCP domains, potentially useful to film functional properties such as gas barrier when filled with clay or plasmonics for gold nanoparticles. We further model this reduced L0 in DIA processed films with a scaling approach to correlate the final structure to degree of polymerization, N. Our results reveal that DIA, a roll-to-roll (R2R) compatible DSA method, can enable real-time manufacture of nanofilled block copolymers for functional applications.
AB - Block copolymers (BCPs) can function as nanoscale templates to organize nanoparticles within selective domains. Most functional applications of nanofilled BCPs generally require a high loading of nanoparticles, which is difficult to achieve due to particle aggregation, slow kinetics of ordering, and disruption of block copolymer order. A key parameter is the periodic domain spacing, L0, which is important for tuning functional properties. We demonstrate direct immersion annealing (DIA) as a promising directed self-assembly (DSA) method to overcome these problems. DIA is shown to fully order highly filled (10.5 vol % Au-PSrPMMA nanoparticles) lamellar poly(styrene-b-methyl methacrylate) (PS-PMMA) BCP films, whose lamellar ordering is practically unimpeded by filler loading. Neutron reflection (NR) further confirms that DIA sharpens the interfacial width between PS-PMMA domains by ∼20%. In situ NR studies further reveal that DIA predominantly induced film ordering in a 5 wt % anisotropic organoclay (C93A) filled PS-PMMA film in less than 30 s! In contrast, identical C93A nanofilled PS-PMMA films that were thermally annealed (19 h at 160 °C) only exhibit partial ordering near the free surface. DIA films also exhibit ∼50% reduced L0, resulting in twice the number of BCP domains, potentially useful to film functional properties such as gas barrier when filled with clay or plasmonics for gold nanoparticles. We further model this reduced L0 in DIA processed films with a scaling approach to correlate the final structure to degree of polymerization, N. Our results reveal that DIA, a roll-to-roll (R2R) compatible DSA method, can enable real-time manufacture of nanofilled block copolymers for functional applications.
UR - http://www.scopus.com/inward/record.url?scp=84997684031&partnerID=8YFLogxK
U2 - 10.1021/acs.macromol.6b01690
DO - 10.1021/acs.macromol.6b01690
M3 - Article
AN - SCOPUS:84997684031
VL - 49
SP - 8563
EP - 8571
JO - Macromolecules
JF - Macromolecules
SN - 0024-9297
IS - 22
ER -