Conformational Switching in Nanofibers: A New Bioelectronic Interface for Gas Sensors

Özenler, Sezer; Yucel, Muge; Yıldız, Ümit Hakan

doi:10.1201/9781003056003-4

Cited by 1 publication

(1 citation statement)

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“… 16 Compared with gradient electrostatic LBL, the rLBL approach offers four major benefits, namely, (i) the covalent bond offers excellent stability, (ii) rLBL does not require additional cross-linking, (iii) rLBL may be used in aqueous or organic reaction types, and (iv) the latest deposited layer does not disassemble the previously deposited layer. 17 , 18 Using rLBL assembly with the aza-Michael reaction of branched polyethylenimine (BPEI) and polyester (PE) on the isocyanate-functionalized gold surface, our recent work showed that a 400 nm robust electroactive nanogel coating structure, allowing effective permeability mass and charge transfer, can be created. Results from X-ray photoelectron spectroscopy (XPS) depth profiling revealed that both polymers were present in each layer due to the presence of multiple functional groups in addition to the BPEI and PE intense layers of the nanogel.…”

Section: Introductionmentioning

confidence: 99%

Thickness Gradient in Polymer Coating by Reactive Layer-by-Layer Assembly on Solid Substrate

Özenler,

Alkan,

Gunay

et al. 2023

ACS Omega

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The study describes a simple yet robust methodology for forming gradients in polymer coatings with nanometer-thickness precision. The thickness gradients of 0–20 nm in the coating are obtained by a reactive layer-by-layer assembly of polyester and polyethylenimine on gold substrates. Three parameters are important in forming thickness gradients: (i) the incubation time, (ii) the incubation concentration of the polymer solutions, and (iii) the tilt angle of the gold substrate during the dipping process. After examining these parameters, the characterization of the anisotropic surface obtained under the best conditions is presented in the manuscript. The thickness profile and nanomechanical characterization of the polymer gradients are characterized by atomic force microscopy. The roughness analysis has demonstrated that the coating exhibited decreasing roughness with increasing thickness. On the other hand, Young’s moduli of the thin and thick coatings are 0.50 and 1.4 MPa, respectively, which assured an increase in mechanical stability with increasing coating thickness. Angle-dependent infrared spectroscopy reveals that the C–O–C ester groups of the polyesters exhibit a perpendicular orientation to the surface, while the CC groups are parallel to the surface. The surface properties of the polymer gradients are explored by fluorescence microscopy, proving that the dye’s fluorescence intensity increases as the coating thickness increases. The significant benefit of the suggested methodology is that it promises thickness control of gradients in the coating as a consequence of the fast reaction kinetics between layers and the reaction time.

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Section: Introductionmentioning

confidence: 99%