Functionalization of Poly(<i>para</i>‐xylylene)s—Opportunities and Challenges as Coating Material

Moss, Tobias; Greiner, Andreas

doi:10.1002/admi.201901858

Cited by 32 publications

(20 citation statements)

References 99 publications

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“…Because of the stable low pressure plasma process and no molecular collisions present, the polymer can achieve more similar content of each monomer moiety resulting in better thermal stability which is further analyzed and compared to the classical VDP of poly(p-xylylene). Here, the activation step has been realized in situ by plasma, whereas previous studies showed ( Moss and Greiner, 2020 ) that additional groups such as esters or UV post-treatment can be introduced in order to enable this enhanced linkage and thus stability.…”

Section: Resultsmentioning

confidence: 99%

Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications

et al. 2021

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Summary The endeavors to develop manufacturing methods that can enhance polymer and composite structures in spacecraft have led to much research and innovation over many decades. However, the thermal stability, intrinsic material stress, and anisotropic substrate properties pose significant challenges and inhibit the use of previously proposed solutions under extreme space environment. Here, we overcome these issues by developing a custom-designed, plasma-enhanced cross-linked poly(p-xylylene):diamond-like carbon superlattice material that enables enhanced mechanical coupling with the soft polymeric and composite materials, which in turn can be applied to large 3D engineering structures. The superlattice structure developed forms an integral part with the substrate and results in a space qualifiable carbon-fiber-reinforced polymer featuring 10–20 times greater resistance to cracking without affecting the stiffness of dimensionally stable structures. This innovation paves the way for the next generation of advanced ultra-stable composites for upcoming optical and radar instrument space programs and advanced engineering applications.

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Section: Resultsmentioning

confidence: 99%

Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications

et al. 2021

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“…The CVD process does not require any catalyst, initiator or solvent. The reactive species from chemical precursors are preformed in the vapor phase and spontaneously polymerize without any side products or decomposition of the monomers . The chemical inertness, high purity, flexibility, mechanical strength, and stability of parylenes offer enormous potential in surface modification, optoelectronics, and drug delivery systems and have demonstrated technological utility for coatings of industrial products (e.g., clinically used biomaterials and biomedical devices). − Integrating the CVD polymerization process with a template-driven approach can significantly advance capabilities for molecularly controlled structuring of parylenes with tailored shapes, sizes, and chemistries.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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Poly(para-xylylene)s are a unique class of chemical vapor deposition (CVD)-based polymers, generally referred to their tradename "parylenes", widely used as a protective coating and insulating layer in electronics, especially in printed circuit boards and optical and biomedical devices. Due to their unique synthesis via CVD polymerization, parylene coating conforms to a surface; however, molecularly controlled structuring of parylene particles with precise spatial arrangements over multiple hierarchical levels, tailored shapes, sizes, and porosities has not been realized. Here, we report metal−organic framework (MOF)-templated cyclophane-based CVD polymerization with morphology and porosity transcription of the host framework. This catalyst-and initiator-free template approach forms a CVD polymer in three-dimensional (3D) confined nanospaces. The paraxylene diradicals (monomers) formed during CVD polymerization using [2.2]paracyclophane (PCP) as a precursor molecule (Gorham process) diffuse into confined nanochannels of the crystalline 3D HKUST-1 MOF and spontaneously polymerize to generate parylene@MOF composites. Here, MOF confined geometries can act as a sacrificial template and, upon removal of the coordinating metal ions, facilitate the formation of templated parylene particles with the transcription of the parent crystal HKUST-1 morphology and porosity. The templated morphologies depend on subtle changes of the chemical composition of the CVD precursors as indicated by clear morphological differences observed for parylene particles synthesized from pristine and chlorosubstituted PCPs. Atomistic ab initio and classical molecular dynamics simulations and energy barrier calculations using the density functional theory−nudged elastic band method of the poly(para-xylylene) precursors in an HKUST-1 confinement were performed to study the mechanism of the molecularly controlled structuring of parylenes. The structuring process is driven by the differences in the diffusion properties of diradicals precursors inside the HKUST-1 MOF. MOF-templated CVD polymerization with implementation of 3D spatial arrangements establishes a new platform for the synthesis of functional parylene polymer particles with structurally controlled morphologies, where molecularly imprinted structuring is modulated by the choice of both the template and the CVD precursor.

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“…Parylene C has received considerable research attention because of its biocompatibility, chemical inertness, and low moisture permeability, which result in it having suitable barrier properties [24][25][26][27][28]. This material has been used in implantable medical devices, such as implantable nerve recording electrodes [29,30], implantable biomedical chips [31,32], drug delivery systems [32,33], spinal cord stimulators [34,35], and cardiac rhythm devices.…”

Section: Introductionmentioning

confidence: 99%

Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers

Hsieh

Huang

2022

Materials

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The use of poly-(para-chloro-xylylene) (Parylene C) in microelectromechanical systems and medical devices has increased rapidly. However, little research has been conducted on the wettability and surface roughness of Parylene C after being soaked in solutions. In this study, the contact angle and surface roughness (arithmetic average of roughness) of Parylene C on three-dimensional (3D)-printed photopolymer in 10% sodium hydroxide, 10% ammonium hydroxide, and 100% phosphate-buffered saline (PBS) solutions were investigated using a commercial contact angle measurement system and laser confocal microscope, respectively. The collected data indicated that 10% ammonium hydroxide had no major effect on the contact angle of Parylene C on a substrate, with a Shore A hardness of 50. However, 10% sodium hydroxide, 10% ammonium hydroxide, and 100% PBS considerably affected the contact angle of Parylene C on a substrate with a Shore A hardness of 85. Substrates with Parylene C coating exhibited lower surface roughness than uncoated substrates. The substrates coated with Parylene C that were soaked in 10% ammonium hydroxide exhibited high surface roughness. The aforementioned results indicate that 3D-printed photopolymers coated with Parylene C can offer potential benefits when used in biocompatible devices.

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Functionalization of Poly(para‐xylylene)s—Opportunities and Challenges as Coating Material

Cited by 32 publications

References 99 publications

Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications

Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications

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

Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers

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