Kim Dong Hyup, Kim So Youn
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea.
ACS Cent Sci. 2019 Sep 25;5(9):1562-1571. doi: 10.1021/acscentsci.9b00560. Epub 2019 Sep 10.
In polymer thin films, the bottom polymer chains are irreversibly adsorbed onto the substrates creating an ultrathin layer. Although this thin layer (only a few nanometers thick) governs all film properties, an understanding of this adsorbed layer remains elusive, and thus, its effective control has yet to be achieved, particularly in block copolymer (BCP) thin films. Herein, we employ self-assembled copolymer adsorption layers (SCALs), transferred from the air/water interfacial self-assembly of BCPs, as an effective control of the adsorbed layer in BCP thin films. SCALs replace the natural adsorbed layer, irreversibly adsorbing onto the substrates when other BCP is additionally coated on the SCALs. We further show that SCALs guide the thin film nanostructures because they provide topological restrictions and enthalpic/entropic preferences for a BCP self-assembly. The SCAL-induced self-assembly enables unprecedented control of nanostructures, creating novel nanopatterns such as spacing-controlled hole/dot patterns, dotted-line patterns, dash-line patterns, and anisotropic cluster patterns with exceptional controllability.
在聚合物薄膜中，底部的聚合物链不可逆地吸附在基底上，形成一个超薄层。尽管这个薄层（只有几纳米厚）决定了所有薄膜的性能，但对这个吸附层的理解仍然难以捉摸，因此，尚未实现对其的有效控制，尤其是在嵌段共聚物（BCP）薄膜中。在此，我们采用从BCP的空气/水界面自组装转移而来的自组装共聚物吸附层（SCALs），作为对BCP薄膜中吸附层的有效控制。当在SCALs上额外涂覆其他BCP时，SCALs会取代天然吸附层，并不可逆地吸附在基底上。我们进一步表明，SCALs引导薄膜纳米结构，因为它们为BCP自组装提供了拓扑限制以及焓/熵偏好。SCAL诱导的自组装实现了对纳米结构前所未有的控制，创造出了新型纳米图案，如间距可控的孔/点图案、虚线图案、短线图案以及具有卓越可控性的各向异性簇图案。
