DOI: 10.34808/9hcq-rg42
title: The influence of chitosan hydrogel cross-linking by agarose on coating physico-chemical properties

description: This dataset contains various physicochemical analyses showing the effect of different concentration of chitosan and the cross-linking agent agarose. Each sample is labeled by C and A representing chitosan and agarose concentrations, respectively, while the exact amounts are depicted in the attached table.
 

Fourier-transform infrared (FT-IR) spectroscopy analysis was carried out with a Bruker IFS66 spectrometer. The spectra were obtained in the spectral range 5000–400 cm−1. Samples were prepared by the standard CaF2 pellet method. X-ray Photoelectron Spectroscopy (XPS) analysis was carried out with Escalab 250Xi (ThermoFisher Scientific), operating AlKα source and 250 μm spot diameter, under low-energy e− and Ar+ flow for charge compensation. Peak deconvolution was done in Avantage v.59921 provided by the spectroscope manufacturer, with final calibration on adventitious carbon C 1s at 284.7 eV.
The contact angle was measured using a Kruss (Hamburg, Germany) DSA100 goniometer. Samples for measurements were prepared by applying 5 µL of hydrogel to a glass plate and allowed to evaporate at room temperature. A 4 µL drop of water was applied to the surface thus created using a syringe. The contact angle on both sides of the droplet was then measured using a CCD camera, and the average contact angle was determined with ADVANCE software using the Young-Laplace method. Each measurement was repeated 20 times. Kinematic viscosity was measured using a 4-mm diameter flow cup. 100 ml each of hydrogel and acetic acid solutions were prepared. Each liquid at room temperature was passed through the effluent cup, the flow time was measured using a stopwatch. Each measurement was repeated 3 times.
Kinematic viscosity was determined according to the ASTM standard [39]. The ζ-potential was measured using the Electrophoretic Light Scattering method (ELS). Measurements were carried out on the Litesizer 500, ANTON-PAAR for ELS &gt; ±1000 mV. Transmission electron microscopy (TEM) images were performed using a Tecnai G2 Spirit BioTWIN by FEI operated at 120 kV.
Atomic Force Microscopy (AFM) imaging was performed using NTegra Prima (NT-MDT, Russia). To enable scanning a surface of GCEs, a dedicated holder was made, adapted to be mounted in the base of the atomic force microscope and performing measurements in scan-by-head configuration. To minimize the probe interaction with the hydrogel surface, a semi-contact mode (“tapping”) of scanning was utilized, by oscillating the AFM probe near its resonance frequency. This intermittent contact reduces the lateral forces between the probe and the sample, minimizing potential damage to the surface. The amplitude of the cantilever oscillation is monitored during scanning using a feedback loop. Probes NSG30 (TipsNano) were used. Their geometric parameters are as follows: cantilever length 125 ± 10 mm, width 30 ± 7.5 mm, thickness 4 ± 7.5 mm, tip curvature radius 10 nm. The resonant frequency is 244.5 kHz. Each measurement was represented by two maps: a topographic and a deflection (DFL), showing changes in the oscillation amplitude.

 
These results are part of the manuscript: https://www.sciencedirect.com/science/article/pii/S156753942400166X