Ultrathin and Conformal Initiated Chemical-Vapor-Deposited Layers of Systematically Varied Surface Energy for Controlling the Directed Self-Assembly of Block CoPolymers

Directed self-assembly (DSA) of block copolymer (BCP) thin films is a promising approach to enable next-generation patterning at increasingly smaller length scales. DSA utilizes interfacial wetting layers to force the BCP domains to self-assemble with the desired orientation with respect to the substrate. Here, we demonstrate that initiated chemical-vapor-deposited (iCVD) polydivinylbenzene (pDVB) ultrathin films can direct the self-assembly of poly­(styrene-<i>block</i>-methylmethacrylate). We found that the methyl radicals formed at increased filament temperatures during the iCVD process result in the backbone methylation of pDVB. By tuning the degree of backbone methylation, we systematically changed the wetting properties of the iCVD pDVB from a slight poly­(methylmethacrylate) preference to complete poly­(styrene) preference. Additionally, we utilize the conformal nature of the iCVD to form a wetting layer over a topographical line and space pattern, which is subsequently used to produce self-assembled BCP films with both perpendicular orientation and long-range alignment

A Group of Cyclic Siloxane and Silazane Polymer Films as Nanoscale Electrolytes for Microbattery Architectures

Nanoscale (10–50 nm) thin films of cyclic siloxane and silazane polymers were synthesized by initiated chemical vapor deposition (iCVD). We have previously demonstrated that the non-line-of-sight iCVD synthesis process can create uniform conformal coverage of these films over complex nonplanar surfaces. This work will introduce the protocols used to convert these dielectric polymer films into ionic conductors at room temperature. The excellent thickness and morphological stability of these films will be demonstrated along with experiments that determine the ion content in the films. Finally, computational calculations will be used to elucidate the chemical nature of the ion doping and transport processes. These nanoscale, conformal, ionically conducting polymer thin films are attractive as a novel class of nanoscale electrolytes for emerging miniaturized or microbattery architectures such as three-dimensional (3D) batteries which combine high energy (due to high surface area) and power density (due to short ionic transport lengths) within small areal footprints