Influence of high energy electron irradiation on the network structure of gelatin hydrogels as investigated by small-angle X-ray scattering (SAXS)

Wisotzki, Emilia I.; Tempesti, Paolo; Fratini, Emiliano; Mayr, Stefan

doi:10.1039/c7cp00195a

Cited by 37 publications

(47 citation statements)

References 36 publications

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“…Such feature indicates that the network structures can be described by a combination of polymer concentration fluctuations at the high q region and density differences of static inhomogeneities at the low q region, which are represented by the Lorentzin-type function and the Debye-Bueche function, respectively 29 . However, we found that a large uncertainty was associated with estimating the characteristic length of inhomogeneities because we only observed a constant slope of -4 at a low q region, indicating that the characteristic length of inhomogeneities was too large to be probed by the SAXS analysis 30 . Consequently, we employed a combined equation of the approximated Debye-Bueche function and the Lorentzian type function to predict the scattering intensity I(q)…”

mentioning

confidence: 73%

Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

Ahn¹,

Ryu²,

Song³

et al. 2018

Preprint

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Polysaccharides, such as hyaluronic acid, alginate, or chitosan, can be modified by addition of reactive functional groups to enable chemical crosslinking. Here, we studied how different methods of crosslinking methacrylate-functionalized chitosan affected the network structures of the resulting hydrogels. We then investigated how the porous network structures in turn influenced stiffness, macromolecular diffusion through the pores, and enzymatic degradation. All these properties are relevant for utilization of the chemically crosslinked hydrogels in biomedical applications, including tissue engineering and delivery of therapeutic agents. We made chitosan hydrogels using four crosslinking methods, which differ by type and by reaction kinetics. We found that four chitosan hydrogels having identical polymer fractions at an equilibrium swelling exhibited marked differences in their shear moduli, rate of dextran diffusion, and especially their enzymatic degradation behaviors. We inferred that these differences originated in variations among network structures, which were characterized by the formation of chain bundles and associated network heterogeneity as determined by small-angle X-ray scattering analysis.

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mentioning

confidence: 73%

Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

Ahn¹,

Ryu²,

Song³

et al. 2018

Preprint

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“…It indicates there is mass fractal and the ion-rich domains are dispersed as interconnected (branched) networks, confirming the formation of ion channels in our material 25 . Besides, the scattering shoulder at low scattering vectors, as indicated by an arrow, suggests long-range order of the ion channels 26 . The mesh size of these channels is estimated as , i.e., about 10-nm diameter.…”

Section: Resultsmentioning

confidence: 99%

A highly transparent and ultra-stretchable conductor with stable conductivity during large deformation

2019

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Intrinsically stretchable conductors have undergone rapid development in the past few years and a variety of strategies have been established to improve their electro-mechanical properties. However, ranging from electronically to ionically conductive materials, they are usually vulnerable either to large deformation or at high/low temperatures, mainly due to the fact that conductive domains are generally incompatible with neighboring elastic networks. This is a problem that is usually overlooked and remains challenging to address. Here, we introduce synergistic effect between conductive zwitterionic nanochannels and dynamic hydrogen-bonding networks to break the limitations. The conductor is highly transparent (>90% transmittance), ultra-stretchable (>10,000% strain), high-modulus (>2 MPa Young’s modulus), self-healing, and capable of maintaining stable conductivity during large deformation and at different temperatures. Transparent integrated systems are further demonstrated via 3D printing of its precursor and could achieve diverse sensory capabilities towards strain, temperature, humidity, etc., and even recognition of different liquids.

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Section: Resultsmentioning

confidence: 99%

“…Furthermore, there were electron density differences between the soft and hard segments in the SMPU matrix as well as between the SMPU matrix and SiO 2 particles in the SiO 2 /SMPU, which led to electron density fluctuations at the above interfaces. The interphase interaction between molecular chains of the SMPU matrix and SiO 2 particles is the main cause of a positive deviation[37].On one hand, there are many formed defects at the interfaces between the hard and soft segments as well as between the SMPU matrix and SiO 2 particles. The defects between them further result in the generation of space charges, which affects the electron density[38].…”

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confidence: 99%

The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process

Shi

Wang

et al. 2020

Polymers

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In order to further understand the shape memory mechanism of a silicon dioxide/shape memory polyurethane (SiO2/SMPU) composite, the thermodynamic properties and shape memory behaviors of prepared SiO2/SMPU were characterized. Dynamic changes in the molecular orientation and interphase structures of SiO2/SMPU during a shape memory cycle were then discussed according to the small angle X-ray scattering theory, Guinier’s law, Porod approximation, and fractal dimension theorem. In this paper, a dynamic mechanical analyzer (DMA) helped to determine the glass transition start temperature (Tg) by taking the onset point of the sigmoidal change in the storage modulus, while transition temperature (Ttrans) was defined by the peak of tan δ, then the test and the calculated results indicated that the Tg of SiO2/SMPU was 50.4 °C, and the Ttrans of SiO2/SMPU was 72.18 °C. SiO2/SMPU showed good shape memory performance. The programmed SiO2/SMPU showed quite obvious microphase separation and molecular orientation. Large-size sheets and long-period structures were formed in the programmed SiO2/SMPU, which increases the electron density difference. Furthermore, some hard segments had been rearranged, and their gyration radii decreased. In addition, several defects formed at the interfaces of SiO2/SMPU, which caused the generation of space charges, thus leading to local electron density fluctuations. The blurred interphase structure and the intermediate layer formed in the programmed SiO2/SMPU and there was evident crystal damage and chemical bond breakage in the recovered SiO2/SMPU. Finally, the original and recovered SiO2/SMPU samples belong to the surface fractal system, but the programmed sample belongs to the mass fractal and reforms two-phase structures. This study provides an insight into the shape memory mechanism of the SiO2/SMPU composite.

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Influence of high energy electron irradiation on the network structure of gelatin hydrogels as investigated by small-angle X-ray scattering (SAXS)

Cited by 37 publications

References 36 publications

Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

Effects of Crosslinking Methods on Network Structure and Enzymatic Degradation of Methacrylate-Functionalized Chitosan Hydrogel

A highly transparent and ultra-stretchable conductor with stable conductivity during large deformation

The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process

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