Design Strategies for Structurally Controlled Polymer Surfaces via Cyclophane‐Based CVD Polymerization and Post‐CVD Fabrication

Abstract

Molecular structuring of soft matter with precise arrangements over multiple hierarchical levels, especially on polymer surfaces, and enabling their post‐synthetic modulation has tremendous potential for application in molecular engineering and interfacial science. Here, recent research and developments in design strategies for structurally controlled polymer surfaces via cyclophane‐based chemical vapor deposition (CVD) polymerization with precise control over chemical functionalities and post‐CVD fabrication via orthogonal surface functionalization that facilitates the formation of designable biointerfaces are summarized. Particular discussion about innovative approaches for the templated synthesis of shape‐controlled CVD polymers, ranging from 1D to 3D architecture, including inside confined nanochannels, nanofibers/nanowires synthesis into an anisotropic media such as liquid crystals, and CVD polymer nanohelices via hierarchical chirality transfer across multiple length scales is provided. Aiming at multifunctional polymer surfaces via CVD copolymerization of multiple precursors, the structural and functional design of the fundamental [2.2]paracyclophane (PCP) precursor molecules, that is, functional CVD monomer chemistry is also described. Technologically advanced and innovative surface deposition techniques toward topological micro‐ and nanostructuring, including microcontact printing, photopatterning, photomask, and lithographic techniques such as dip‐pen nanolithography, showcasing research from the authors’ laboratories as well as other's relevant important findings in this evolving field are highlighted that have introduced new programmable CVD polymerization capabilities. Perspectives, current limitations, and future considerations are provided.

Solid and Hollow Poly(p-xylylene) Particles SynthesisviaMetal–Organic Framework-Templated Chemical Vapor Polymerization

“…The synthetic design of the fundamental cyclophane precursors with chemical functionalities that are compatible with CVD conditions and can be immobilized inside the MOF crystalline networks (such as thiol, hydroxyl, and amino groups) − would be a crucial step. These chemical functionalities, subsequent to the polymerization, can be used as anchoring sites for tailoring post-CVD surface engineering, tremendously increasing the potential for molecularly controlled parylene-derived porous functional materials.…”

Vapor-Deposited Polymer Films and Structure: Methods and Applications

“…26 Parylene, especially parylene C (mono-chloro-PCP), is known for its high biocompatibility, anticorrosive properties, and antibacterial properties, making it suitable as a biomaterial. 18 Other parylenes that have been fabricated with CVD include parylene N (nonfunctionalized), parylene D (dichloro-PCP), and parylene-HT (tetra-fluoro-PCP).…”

“…Currently, the research trend in polymers has started to shift from 2D substrates to the fabrication of free-standing nanomaterials such as nanoparticles, nanotubes, and nanowires. 18 Polymer nanostructures possess advantages over other types of nanomaterials, as they are easily tunable, their structures can be altered to produce structures with various compositions, morpholo-gies, sizes, and surface properties. 19 Vapor deposition has emerged as a promising technology for polymer synthesis because of its unique properties over traditional solvent polymerization.…”

“…Tian et al deposited parylene AF4 (octafluoro-[2.2]paracyclophane) onto polydimethylsiloxan (PDMS) to create a surface with wrinkled surface topography, low surface free energy, and negative surface charge properties that exhibited antifouling performance against bacteria and algae. 86 A variety of functionalized groups used in parylene CVD have been fully reviewed by Hassan et al 18 Sim et al developed a sin-gle-step bifacial vertical deposition method to address the issue of thickness variations on both sides of the sample that arise during traditional horizontal deposition. 106 In another study, Hu et al used a sublimating ice template as the CVD substrate to produce an advanced functional porous material that is capable of conjugating with thiol-Michael click chemistry.…”

“…26 Parylene, especially parylene C (mono-chloro-PCP), is known for its high biocompatibility, anticorrosive properties, and antibacterial properties, making it suitable as a biomaterial. 18 Other parylenes that have been fabricated with CVD include parylene N (nonfunctionalized), parylene D (di-chloro-PCP), and parylene-HT (tetra-fluoro-PCP). Tian et al deposited parylene AF4 (octafluoro-[2.2]paracyclophane) onto polydimethylsiloxan (PDMS) to create a surface with wrinkled surface topography, low surface free energy, and negative surface charge properties that exhibited antifouling performance against bacteria and algae.…”