Nanomechanical characterization and molecular mechanism study of nanoparticle reinforced and cross-linked chitosan biopolymer

Rath, Amrita; Mathesan, Santhosh; Ghosh, Pijush

doi:10.1016/j.jmbbm.2015.10.005

Cited by 30 publications

(18 citation statements)

References 31 publications

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“…Nanoindentation, in particular, is increasingly used in the field of bionanocomposite materials, for which understanding the interface/interphase nature is crucial in order to fully exploit the size effect of the nanoparticles with the ultimate goal of improving the final performance of the biopolymer phase. However, according to the literature, the information on the use of nanoindentation for bionanocomposite materials pertains almost exclusively to stand-alone films [45][46][47][48][49][50]. In practice, today's market applications (e.g., displays, photovoltaic cells, and packaging materials) employ biopolymer nanocomposites in the form of thin films and coatings laid on a supporting substrates, in most cases flexible materials such as plastics [14].…”

Section: Discussionmentioning

confidence: 99%

Mechanical behavior of biopolymer composite coatings on plastic films by depth-sensing indentation – A nanoscale study

Rovera

Cozzolino

Ghaani

et al. 2018

Journal of Colloid and Interface Science

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Fundamental physical behaviors of materials at the nanoscale level are crucial when local aspects govern the macroscale performance of nanocomposites, e.g., interface and surface phenomena. Because of the increasing interest in biopolymer nanocomposite coatings for many different applications (e.g., optical devices, displays/screens, and packaging), this work investigates the potential of nanoindentation as a method for clarifying the interplay between distinct phases (i.e., organic and inorganic) at local level in thin biopolymer films loaded with nanoparticles. The nanomechanical features of pullulan nanocomposite coatings laid on polyethylene terephthalate (PET) were quantified in terms of elastic modulus (E), hardness (H), and creep (C) through an instrumented indentation test composed of a loading-holding-unloading cycle. Colloidal silica (CS) and cellulose nanocrystals (CNCs) were used as spherical and rod-like nanoparticles, respectively.An overall reinforcing effect was shown for all nanocomposite coatings over the pristine (unfilled) pullulan coating. A size effect was also disclosed for the CS-loaded surfaces, with the highest E value recorded for the largest particles (8.19 ± 0.35 GPa) and the highest H value belonging to the smallest ones (395.41 ± 25.22 MPa). Comparing CS and CNCs, the addition of spherical nanoparticles had a greater effect on the surface hardness than cellulose nanowhiskers (353.50 ± 83.52 MPa and 321.36 ± 43.26 MPa, respectively). As for the elastic modulus, the addition of CS did not provide any improvement over both the bare and CNC-loaded pullulan coatings, whereas the coating including CNCs exhibited higher E values (p < 0.05). Finally, CS-loaded pullulan coatings were the best performing in terms of C properties, with an average indentation depth of 16.5 ± 1.85 nm under a load of ~190 μN. These results are discussed in terms of local distribution gradients, surface chemistry of nanoparticles, and how nanoparticle aggregation occurred in the dry nanocomposite coatings.3

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Section: Discussionmentioning

confidence: 99%

Mechanical behavior of biopolymer composite coatings on plastic films by depth-sensing indentation – A nanoscale study

Rovera

Cozzolino

Ghaani

et al. 2018

Journal of Colloid and Interface Science

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“…The idea behind the method was first described in 1999 . Since then, it has found considerable use in the literature, especially for biological samples and composite materials . Due to its ability to determine viscoelastic properties, nanoDMA is especially well suited for the analysis of polymer samples.…”

Section: Methodsmentioning

confidence: 99%

Tailoring the Mechanical Properties of 3D Microstructures Using Visible Light Post‐Manufacturing

et al. 2019

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the laser, where the square of the optical intensity exceeds the threshold needed to initiate polymerization. In this way, very small feature sizes of less than 100 nm can be achieved. [3,4] Microstructures pre pared via DLW have for example been used in microfluidic chips, [5,6] metama terials, [7] or as 3D microscaffolds for cell and tissue engineering. [8] Commercial resist mixtures are available that are well suited for the rapid generation of stable structures. However, when using standard resists, the resulting microstructures are static. In order to further expand the rep ertoire of applications of DLW, new photo resists have to be designed that directly impart functionality onto the structures emerging from the writing process. [9] Our group has been pursuing this goal, pro ducing resists that, e.g., lead to conduc tive, [10] stimuliresponsive, [11] and erasable structures. [12] The mechanical properties of microstructures are critical for their application, especially when used as cell scaf folds. [13] The mechanical properties of microstructures created via DLW can certainly be tuned by careful adjustment of the writing parameters (i.e., laser power and scan speed), but only to a limited extent. [14] Herein, we present the first photoresist for DLW that is capable of generating microstructures whose mechanical properties can be adjusted postwriting, solely The photochemistry of anthracene, a new class of photoresist for direct laser writing, is used to enable visible-light-gated control over the mechanical properties of 3D microstructures post-manufacturing. The mechanical and viscoelastic properties (hardness, complex elastic modulus, and loss factor) of the microstructures are measured over the course of irradiation via dynamic mechanical analysis on the nanoscale. Irradiation of the microstructures leads to a strong hardening and stiffening effect due to the generation of additional crosslinks through the photodimerization of the anthracene functionalities. A relationship between the loss of fluorescence-a consequence of the photodimerization-and changes in the mechanical properties isestablished. The fluorescence thus serves as a proxy read-out for the mechanical properties. These photoresponsive microstructures can potentially be used as "mechanical blank slates": their mechanical properties can be readily adjusted using visible light to serve the demands of different applications and read out using their fluorescence. 3D MicrostructuresDirect laser writing (DLW) is the only manufacturing tech nique capable of producing truly 3D structures on the micro scopic scale. [1] What differentiates DLW from conventional 3Dprinting techniques is the fact that it exploits twophoton absorption (TPA) to initiate polymerizations. While single photon absorption (SPA) is proportional to the optical inten sity, TPA is proportional to the square of the optical intensity. [2] Thus, polymerization will only take place in the focal volume of

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“…The machine provides a surface topography of constant contact force in scanning probe microscopy (SPM) mode. In addition, it provides a load versus depth of penetration (P‐h) plot in the nanoindentation mode . A diamond indenter is used for this purpose.…”

Section: Methodsmentioning

confidence: 99%

Structure and stability analysis of biocompatible hydroxyapatite reinforced chitosan nanocomposite

Chakraborty¹,

Bhowmik

2018

Polymer Composites

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Nano‐hydroxyapatite has been used in multifunctional potential clinical applications where certain particle size distribution and morphology are required. The hydroxyapatite/chitosan composites were prepared using in situ co‐precipitation technique, influence of the reaction temperature on the crystallization and particle growth of the synthesized nano‐hydroxyapatite were examined. It was observed that the increase in synthesis temperature had a great influence on particle size and crystal structure of nano‐hydroxyapatite, whereas, the low temperature showed inhabitation of the hydroxyapatite growth in c‐direction and low crystallinity which was confirmed using XRD and electron diffraction pattern of TEM micrographs. The molar ratio of the bone‐like apatite layer for composite prepared at 70°C was higher was higher than the composites prepared at lower temperatures (40°C and −5°C). The AFM images of −5°C, 40°C, and 70°C n‐HAp/CTS composite display presence of CTS rich domains. These CTS rich and domains are made of smaller globular shaped particles in which, n‐HAp particles are embedded in the polymer matrix. The SBF degraded AFM surface topography of the composites shows the CTS is degraded fast rather the n‐HAp. The elastic modulus determined from nanoindentation of −5°C, 40°C, and 70°C n‐HAp/CTS composites are 17.91, 24.56, and 30.62 GPa respectively. Hardness values of the three composites in the same order were found to be 0.86, 1.35, and 1.74 GPa, respectively. Macro‐mechanical tests showed significant enhancement in elastic modulus, coefficient of friction and hardness of 70°C n‐HAp/CTS composites over −5°C and 40°C n‐HAp/CTS. However, the SBF degraded samples also performed moderate improvement in nanomechanical property. POLYM. COMPOS., 39:E573–E583, 2018. © 2018 Society of Plastics Engineers

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Nanomechanical characterization and molecular mechanism study of nanoparticle reinforced and cross-linked chitosan biopolymer

Cited by 30 publications

References 31 publications

Mechanical behavior of biopolymer composite coatings on plastic films by depth-sensing indentation – A nanoscale study

Mechanical behavior of biopolymer composite coatings on plastic films by depth-sensing indentation – A nanoscale study

Tailoring the Mechanical Properties of 3D Microstructures Using Visible Light Post‐Manufacturing

Structure and stability analysis of biocompatible hydroxyapatite reinforced chitosan nanocomposite

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