Controlling the Degree of Crystallinity and Preferred Crystallographic Orientation in Poly‐Perfluorodecylacrylate Thin Films by Initiated Chemical Vapor Deposition

Abstract

Preferred crystallographic orientation (texture) in thin films of technologically important materials frequently has a strong effect on the properties of these films and is important for stable surface properties. The deposition of organized molecular films of a poly‐perfluorodecylacrylate, poly‐(1H,1H,2H,2H‐perfluorodecyl acrylate) (p‐PFDA), by initiated chemical vapor deposition (iCVD) is described. The tendency of p‐PFDA to crystallize in a smectic B phase has been reported in films prepared from solution but not for those using a CVD technique. The degree of crystallinity and the preferred orientation of the perfluoro side chains, either parallel or perpendicular to the surface, are controlled by tuning the CVD process parameters (i.e., initiator to monomer flow rate ratio, filament temperature, and substrate temperature). Films with no observable X‐ray diffraction patterns are also achieved. The observed differences in crystal texture strongly impact the observed water contact angles (150° to 130°, advancing) and corresponding hysteresis behavior. Low hysteresis (<7°) is associated with high crystallinity, particularly when the orientation of the crystallites resulted in the perfluoro side groups being oriented parallel to the surface. The latter texture resulted in smoother film than the texture with the chains oriented perpendicular to the surface and this can be very advantageous for applications in which relatively smooth but still crystalline films are needed.

Desalination by Membrane Distillation using Electrospun Polyamide Fiber Membranes with Surface Fluorination by Chemical Vapor Deposition

“…42,[44][45] iCVD of poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) 42,45 was conducted using a custom-built reactor. The reaction chamber was cylindrical with a diameter of 246 mm and a height of 38 mm.…”

Linker-free grafting of fluorinated polymeric cross-linked network bilayers for durable reduction of ice adhesion

“…[36][37][38] While copolymerization helps by improving the mechanical properties of uoropoly-mers it negatively impacts the surface wettability of the lms due to a decrease in the uorine content. A bilayer strategy reported here for the rst time consists of a relatively thick, mechanically-robust, and highly-cross-linked network which is covered with an ultrathin uorine-rich layer producing coatings with both enhanced mechanical properties and low surface energy which is essential for icephobic applications.…”

Designing Durable Vapor‐Deposited Surfaces for Reduced Hydrate Adhesion

“…[11,13] The reactor was covered with a quartz top (2.5 cm thick) that allows real-time thickness monitoring by reflecting a 633 nm He-Ne laser source (JDS Uniphase) off the substrate/polymer and recording the interference signal intensity as a function of time. The reactor was pumped down by a mechanical Fomblin pump (Leybold, Trivac) and the pressure was monitored with a MKS capacitive gauge.…”

“…[10][11][12] Unlike traditional polymer deposition techniques such as spin-coating, dipping, and ink-jet printing, iCVD provides ways to deposit graded polymers, copolymers which do not have common solvents, and multilayered polymers which are covalently bonded at their interface. [13,14] The conformal nature of the iCVD technique also enables the integration of polymer thin films onto engineering surfaces that have roughened features or nanostructured topography. We recently developed bilayer polymers which are covalently bonded to substrates using an in-situ grafting mechanism.…”