Kinetic analysis of the initiated chemical vapor deposition of poly(vinylpyrrolidone) and poly(4-vinylpyridine)

Janakiraman, S.; Farrell, Steven L.; Hsieh, Chia‐Yun; Smolin, Yuriy Y.; Soroush, Masoud; Lau, Kenneth K. S.

doi:10.1016/j.tsf.2015.04.083

Cited by 15 publications

(15 citation statements)

References 26 publications

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“…where α is the order of reaction; α = 1 for termination via disproportionation or combination, and α = 2 for termination by primary radical termination, consistent with the reported rate laws for solution-based free radical polymerization (Bamford et al, 1959). Previously, the rate law for iCVD kinetics has been expressed as either a quadratic dependence (Lau and Gleason, 2006b,a) or a linear dependence (Janakiraman et al, 2015); whereas here, we adopted this unifying expression to capture the full continuum from quadratic to linear transition as discussed below. The reaction rate coefficient, k, can be calculated using the Arrhenius relation (Laidler, 1984):…”

Section: Rate Laws For the Icvd Of Passupporting

confidence: 79%

“…The empirical rate constant for the linear regime, i.e., 11.517 nm/min, was comparable to the reported values for other iCVD polymerizations. For example, poly(vinylpyrrolidone), also a non-volatile monomer, had an empirical rate constant of approximately 5.26 nm/min in the linear regime (Janakiraman et al, 2015), while a more reactive monomer, cyclohexyl methacrylate, led to an empirical rate constant of ∼100 in the linear regime (Baxamusa and Gleason, 2008). Comparatively, AS belongs to a class of monomers with relatively slow deposition kinetics among the iCVD monomers reported to date.…”

Section: The Order Of Reaction For the Icvd Of Pasmentioning

confidence: 97%

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Initiated Chemical Vapor Deposition Kinetics of Poly(4-aminostyrene)

Khlyustova

Yang

2021

Front. Bioeng. Biotechnol.

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Initiated Chemical Vapor Deposition (iCVD) is a free-radical polymerization technique used to synthesize functional polymer thin films. In the context of drug delivery, the conformality of iCVD coatings and the variety of functional chemical moieties make them excellent materials for encapsulating pharmaceutics. Poly(4-aminostyrene) (PAS) belongs to a class of functionalizable materials, whose primary amine allows decoration of the delivery vehicles with biomolecules that enable targeted delivery or biocompatibility. Understanding kinetics of PAS polymerization in iCVD is crucial for such deployments because drug release kinetics in thin-film encapsulation have been shown to be determined by the film thickness. Nevertheless, the effects of deposition conditions on PAS growth kinetics have not been studied systematically. To bridge that knowledge gap, we report the kinetics of iCVD polymerization as a function of fractional saturation pressure of the monomer (i.e., Pm/Psat) in a dual-regime fashion, with quadratic dependence under low Pm/Psat and linear dependence under high Pm/Psat. We uncovered the critical Pm/Psat value of 0.2, around which the transition also occurs for many other iCVD monomers. Because existing theoretical models for the iCVD process cannot fully explain the dual-regime polymerization kinetics, we drew inspiration from solution-phase polymerization and proposed updated termination mechanisms that account for the transition between two regimes. The reported model builds upon existing iCVD theories and allows the synthesis of PAS thin films with precisely controlled growth rates, which has the potential to accelerate the deployment of iCVD PAS as a novel biomaterial in controlled and targeted drug delivery with designed pharmacokinetics.

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Section: Rate Laws For the Icvd Of Passupporting

confidence: 79%

Section: The Order Of Reaction For the Icvd Of Pasmentioning

confidence: 97%

Initiated Chemical Vapor Deposition Kinetics of Poly(4-aminostyrene)

Khlyustova

Yang

2021

Front. Bioeng. Biotechnol.

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“…By carrying out air or oxygen plasma surface pretreatment of the catheters prior to iCVD, the catheter surface might favor enhanced surface nucleation, polymer growth, and consequently better integration of the polymer with the substrate. Although PHEMA has been selected in this study, primarily due to its widespread adoption as a viable biomaterial, other polymer hydrogels like poly(ethylene oxide) (PEO) and poly(vinylpyrrolidone) (PVP), which have been successfully synthesized by iCVD, might also be good candidates to explore.…”

Section: Resultsmentioning

confidence: 99%

Reduced cell attachment to poly(2‐hydroxyethyl methacrylate)‐coated ventricular catheters in vitro

Hanak

Hsieh

Donaldson³

et al. 2017

J Biomed Mater Res

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The majority of patients with hydrocephalus are dependent on ventriculoperitoneal shunts for diversion of excess cerebrospinal fluid. Unfortunately, these shunts are failure-prone and over half of all life-threatening pediatric failures are caused by obstruction of the ventricular catheter by the brain's resident immune cells, reactive microglia and astrocytes. Poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels are widely used for biomedical implants. The extreme hydrophilicity of PHEMA confers resistance to protein fouling, making it a strong candidate coating for ventricular catheters. With the advent of initiated chemical vapor deposition (iCVD), a solvent-free coating technology that creates a polymer in thin film form on a substrate surface by introducing gaseous reactant species into a vacuum reactor, it is now possible to apply uniform polymer coatings on complex three-dimensional substrate surfaces. iCVD was utilized to coat commercially available ventricular catheters with PHEMA. The chemical structure was confirmed on catheter surfaces using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. PHEMA coating morphology was characterized by scanning electron microscopy. Testing PHEMA-coated catheters against uncoated clinical-grade catheters in an in vitro hydrocephalus catheter bioreactor containing co-cultured astrocytes and microglia revealed significant reductions in cell attachment to PHEMA-coated catheters at both 17-day and 6-week time points. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1268-1279, 2018.

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“…95 Both 1-vinyl-2-pyrolidone (1V2P) and 4-vinylpyrrolidone (4VP) produce iCVD films showing potential as gel electrolytes layers. 96 The chemical compatibility of iCVD 4VP-based hydrogels with nitroaromatic compounds enabled novel sensor designs for explosives detection. 97,98 The reactivity of the nitrogencontaining functional groups has been utilized for post-deposition functionalization by photoactive molecules.…”

Section: Additional Icvd Permeation Control Layersmentioning

confidence: 99%