Nano thin films, self-assembled

The inherent ability of block copolymers to self-assemble into various well-ordered supramolecular structures makes them attractive for numerous technological applications. For instance, thin films self-assembled from block copolymers have been used as building blocks in nanotechnology and materials science [89-91 ]. Block copolymers have been employed directly without further manipulation as nanomaterials [92], or used as self-organized templates for the creation of nanos-tructured materials [92, 93]. Block copolymer blends demonstrated their applicability as patterning templates for the fabrication of well-ordered arrays [94], as well as for nanoscale manufacturing of more complex patterns [95]. The use of amphiphilic block copolymers for templating applications has been reviewed by FOrster [96]. 

The next three chapters (Chapters 9-11) focus on the deposition of nano-structured or microstructured films and entities. Porous oxide thin films are, for example, of great interest due to potential application of these films as low-K dielectrics and in sensors, selective membranes, and photovoltaic applications. One of the key challenges in this area is the problem of controlling, ordering, and combining pore structure over different length scales. Chapter 9 provides an introduction and discussion of evaporation-induced self-assembly (EISA), a method that combines sol-gel synthesis with self-assembly and phase separation to produce films with a tailored pore structure. Chapter 10 describes how nanomaterials can be used as soluble precursors for the preparation of extended... 

Hua F, Shi J, Lvov Y et al (2002) Patterning of layer-by-layer self-assembled multiple types of nanoparticle thin films by lithographic technique. Nano Lett 2(11) 1219-1222... 

Recent studies have been performed on alternative electrode materials. Nano-sonic has developed low modulus, highly conducting thin film electrodes by molecular level self-assembly processing methods capable of maintaining conductivity up to strains of 100% [217, 218]. Recent developments have enabled the reduction of the modulus to less than 1 MPa and an increase in the strain to rupture to 1000% [219]. A version of the material is commercially available under the name Metal Rubber . Delille et al. have developed novel compliant electrodes based on a platinum salt reduction [220]. The platinum salt is dispersed into a host elastomer and immersed in a reducing agent. A maximum conductivity of 1 S cm was observed and conductivity was maintained for strains up to 40%. 

Figure 10.6 Procedure for polymer nanowire fabrication. An aqueous PEDOTtPSS solution was spin-coated on a substrate patterned with a 1.3 ym period grating, then coated with a thin Si02 layer and a PDMS homopolymer brush. A PS-PDMS block-copolymer thin film was then spin-coated and solvent-annealed. The self-assembled block-copolymer patterns were transferred into the underlying PEDOT-.PSS film through a series of reactive ion etching steps employing CF4 and O2 plasmas. (Reprinted with permission from Nano Letters, Nanowire Conductive Polymer Gas Sensor Patterned Using Self-Assembled Block Copolymer Lithography by Y. S. Jung et al., 8, 11. Copyright (2008) American Chemical Society)...

Yoshida, T., K. Miyamoto, N. Hibi, T. Sugiura, H. Minoura, D. Schlettwein, T. Oek-ermann, G. Schneider, and D. Wohrle (1998). Self assembled growth of nano particulate porous ZnO thin film modified by 2,9,16,23-tetrasulfophthalocyanatozinc(II) by one-step electrodeposition. Chem. Lett. 7, 599-600. 

Scanning electron microscopy (SEM) is one of the very useful microscopic methods for the morphological and structural analysis of materials. Larena et al. classified nanopolymers into three groups (1) self-assembled nanostructures (lamellar, lamellar-within-spherical, lamellar-within-cylinder, lamellar-within-lamellar, cylinder within-lamellar, spherical-within-lamellar, and colloidal particles with block copolymers), (2) non-self-assembled nanostructures (dendrimers, hyperbranched polymers, polymer brushes, nanofibers, nanotubes, nanoparticles, nanospheres, nanocapsules, porous materials, and nano-objects), and (3) number of nanoscale dimensions [uD 1 nD (thin films), 2 nD (nanofibers, nanotubes, nanostructures on polymeric surfaces), and 3 nD (nanospheres, nanocapsules, dendrimers, hyperbranched polymers, self-assembled structures, porous materials, nano-objects)] [153]. Most of the polymer blends are immiscible, thermodynamically incompatible, and exhibit multiphase structures depending on the composition and viscosity ratio. They have two types of phase morphology sea-island structure (one phase are dispersed in the matrix in the form of isolated droplets, rods, or platelets) and co-continuous structure (usually formed in dual blends). 

Reproduced with permission from K.G. Yager, E. Lai, C.T. Black, Self-assembled phases of block copolymer blend thin films, ACS Nano 8 (2014) 10582-10588. 

Rider, D.A., Liu, K., Eloi, J.-C. et al. (2008) Nanostructured magnetic thin films from organometallic block copolymers Pyrolysis of self-assembled polystyrene-block-poly(ferrocenylethylmethylsilane). ACS Nano, 2,263. 

---