A design principle of polymers processable into 2D homeotropic order
نویسندگان
چکیده
How to orient polymers homeotropically in thin films has been a long-standing issue in polymer science because polymers intrinsically prefer to lie down. Here we provide a design principle for polymers that are processable into a 2D homeotropic order. The key to this achievement was a recognition that cylindrical polymers can be designed to possess oppositely directed local dipoles in their cross-section, which possibly force polymers to tightly connect bilaterally, affording a 2D rectangular assembly. With a physical assistance of the surface grooves on Teflon sheets that sandwich polymer samples, homeotropic ordering is likely nucleated and gradually propagates upon hot-pressing towards the interior of the film. Consequently, the 2D rectangular lattice is constructed such that its b axis (side chains) aligns along the surface grooves, while its c axis (polymer backbone) aligns homeotropically on a Teflon sheet. This finding paves the way to molecularly engineered 2D polymers with anomalous functions.
منابع مشابه
Faults and fractures detection in 2D seismic data based on principal component analysis
Various approached have been introduced to extract as much as information form seismic image for any specific reservoir or geological study. Modeling of faults and fractures are among the most attracted objects for interpretation in geological study on seismic images that several strategies have been presented for this specific purpose. In this study, we have presented a modified approach of ap...
متن کاملLiquid crystal polymer networks: preparation, properties, and applications of films with patterned molecular alignment.
Monolithically ordered liquid crystal polymer networks are formed by the photoinitiated polymerization of multifunctional liquid crystal monomers. This paper describes the relevant principles and methods, the basic structure-property relationships in terms of mesogenic properties of the monomers, and the mechanical and optical properties of the polymers. Strategies are discussed to control the ...
متن کاملNear-field Raman dichroism of azo-polymers exposed to nanoscale dc electrical and optical poling.
Azobenzene-functionalized polymer films are functional materials, where the (planar vs. homeotropic) orientation of azo-dyes can be used for storing data. In order to characterize the nanoscale 3D orientation of the pigments in sub-10 nm thick polymer films we use two complementary techniques: polarization-controlled tip-enhanced Raman scattering (TERS) microscopy and contact scanning capacity ...
متن کاملClosed-form Molecular Mechanics Formulations for the 3D Local Buckling and 2D Effective Young’s Modulus of the Nanosheets
A closed form three-dimensional solution is presented for determination of the local buckling (cell buckling) load of the nanosheets. Moreover, an expression is proposed for the effective 2D Young’s modulus of the unit cell of the nanosheet. In this regard, a three-dimensional efficient space-frame-like geometrical model with angular and extensional compliances is considered to investigate stab...
متن کاملSelf-Assembled 2D Free-Standing Janus Nanosheets with Single-Layer Thickness
We report the thermodynamically controlled growth of solution-processable and free-standing nanosheets via peptide assembly in two dimensions. By taking advantage of self-sorting between peptide β-strands and hydrocarbon chains, we have demonstrated the formation of Janus 2D structures with single-layer thickness, which enable a predetermined surface heterofunctionalization. A controlled 2D-to-...
متن کامل