Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

• Nur Areisman Mohd Salleh,
• Amalina Muhammad Afifi,
• Fathiah Mohamed Zuki and
• Hanna Sofia SalehHudin

Beilstein J. Nanotechnol. 2025, 16, 286–307, doi:10.3762/bjnano.16.22

• Viscoelasticity is another property relevant to nanofibers, which combines both elastic and viscous responses to deformation. Viscoelastic properties, including storage modulus and loss modulus, can be tested using dynamic mechanical analysis (DMA) or dynamic mechanical thermal analysis (DMTA). This technique

• as the additional parameter [140]. The presence of chitosan in PVA membranes is expected to increase the storage modulus because of the higher stiffness of chitosan chains compared to PVA chains, as reported from DMA tests by Parparita and coworkers [141]. Koosha et al. [59] measured the dynamic

• mechanical and thermal properties of the PVA and chitosan/PVA nanofiber membranes using DMTA and observed an opposite trend of higher storage modulus for the PVA membrane compared to the chitosan/PVA membrane at temperatures lower than 80 °C. The authors explained several possibilities that resulted in this

Electrospun polysuccinimide scaffolds containing different salts as potential wound dressing material

• Veronika Pálos,
• Krisztina S. Nagy,
• Rita Pázmány,
• Krisztina Juriga-Tóth,
• Bálint Budavári,
• Judit Domokos,
• Dóra Szabó,
• Ákos Zsembery and
• Angela Jedlovszky-Hajdu

Beilstein J. Nanotechnol. 2024, 15, 781–796, doi:10.3762/bjnano.15.65

• , including strength and elasticity of the fibrous scaffold, are crucial parameters. Medical gauze has a storage modulus of 1 MPa to 1 GPa [58], while the Young’s modulus of the skin is between 0.1 and 10 kPa, depending on the body parts, layer, and skin age [59]. In our research, we aimed to investigate the

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

• Nghiem Thi Thuong,
• Le Dinh Quang,
• Vu Quoc Cuong,
• Cao Hong Ha,
• Nguyen Ba Lam and
• Seiichi Kawahara

Beilstein J. Nanotechnol. 2024, 15, 168–179, doi:10.3762/bjnano.15.16

• stress at small strains and higher storage modulus than DPNR/GO. Keywords: graft copolymerization; graphene oxide; natural rubber; vinyltriethoxysilane; Introduction The graft copolymerization of natural rubber (NR) has gained significant interest for an extended period. This interest derives from the

• chemical interaction between GO and NR. Dynamic mechanical properties Dynamic mechanical properties of composite samples reveal how much energy is stored or lost during applied cyclic shearing force. Figure 11 shows the dependence of the storage modulus (G'), loss modulus (G''), and loss tangent (tan δ) of

• storage for composite materials. The G' values seemed to depend on the silica content; the higher the silica content, the higher the storage modulus. The dependence of loss modulus (G'') on frequency for DPNR, DPNR/GO, DPNR/GO-VTES(a), and DPNR/GO-VTES(b) exhibited a little difference as shown in Figure

Elasticity, an often-overseen parameter in the development of nanoscale drug delivery systems

• Agnes-Valencia Weiss and
• Marc Schneider

Beilstein J. Nanotechnol. 2023, 14, 1149–1156, doi:10.3762/bjnano.14.95

• implementation of pause segments keeping the force or position constant and monitoring the other variable. This opens the possibility to measure viscoelastic properties determining, in the case of the Zener model, the elastic modules (E0, E1) and the viscosity (η). More recently, the storage modulus E' and the

Antimicrobial and mechanical properties of functionalized textile by nanoarchitectured photoinduced Ag@polymer coating

• Jessica Plé,
• Marine Dabert,
• Helene Lecoq,
• Sophie Hellé,
• Lydie Ploux and
• Lavinia Balan

Beilstein J. Nanotechnol. 2023, 14, 95–109, doi:10.3762/bjnano.14.11

• ). The storage modulus G’ is not significantly affected by the polymer matrix, but changes with the presence of Ag in the coating. Both storage moduli of uncoated and PEG600DA/PETIA-coated textiles are about 1 MPa (1.1 ± 0.1 MPa and 1.0 ± 0.1 MPa, respectively), whereas they are 0.3 ± 0.1 MPa and 0.6

Frequency-dependent nanomechanical profiling for medical diagnosis

• Santiago D. Solares and
• Alexander X. Cartagena-Rivera

Beilstein J. Nanotechnol. 2022, 13, 1483–1489, doi:10.3762/bjnano.13.122

• important features (“biomarkers”) within the data. Finally, the clinician correlates the obtained patient mechanical data with the patient demographics and an aggregate database to make a decision concerning disease stage and therapeutic approaches. Nomenclature: ES – storage modulus, EL – loss modulus, T

Self-assembly of amino acids toward functional biomaterials

• Huan Ren,
• Lifang Wu,
• Lina Tan,
• Yanni Bao,
• Yuchen Ma,
• Yong Jin and
• Qianli Zou

Beilstein J. Nanotechnol. 2021, 12, 1140–1150, doi:10.3762/bjnano.12.85

• storage modulus (G') value of about 2000 Pa, and can be used for imaging three-dimensional cytoskeletal materials. After human mesenchymal stem cells (hMSCs) were cultured for 72 h in the 3D fiber hydrogel, the cell viability in the 3D gel was subsequently verified. Only a few dead cells were observed

A new method for obtaining model-free viscoelastic material properties from atomic force microscopy experiments using discrete integral transform techniques

• Berkin Uluutku,
• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2021, 12, 1063–1077, doi:10.3762/bjnano.12.79

• the retardance: Limitations of Fourier techniques The Fourier representation of the retardance and the relaxance of the material is commonly used in rheology, where the real components of the operators are referred to as storage modulus or storage compliance, respectively, and the imaginary components

Correction: Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2021, 12, 137–138, doi:10.3762/bjnano.12.10

• microscopy (AFM); creep; force mapping; indentation; Kelvin–Voigt; static force spectroscopy (SFS); viscoelasticity; In the “Useful Viscoelastic Quantities” section of the original publication, it is stated that the storage modulus (E′) and storage compliance (J′) are inverses of one another (Equation 10

On the frequency dependence of viscoelastic material characterization with intermittent-contact dynamic atomic force microscopy: avoiding mischaracterization across large frequency ranges

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 1409–1418, doi:10.3762/bjnano.11.125

• help inform dynamic AFM characterization. Keywords: dynamic atomic force microscopy; Generalized Maxwell model; loss modulus; storage modulus; viscoelasticity; Introduction There have been significant methodology developments since the introduction of atomic force microscopy (AFM) in the mid-1980s [1

• viscoelastic Young´s modulus (E) is straightforward when the Poisson’s ratio (ν) is considered time-independent: In the remainder of the manuscript we omit the designation ‘shear’ for simplicity, although in all cases we refer to shear moduli. Figure 2 illustrates loss and storage modulus as function of the

• definition of a single elastic modulus for the material. Furthermore, we see that neither the loss nor the storage modulus exhibit trivial behavior for the examples shown. For example, depending on the frequency range considered, the loss modulus may or may not exhibit monotonic variation, and the slopes of

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• parameters such as storage modulus, loss modulus, loss angle, and compliance. These steps constitute a complete guide to leveraging AFM-SFS data to estimate key material parameters, with a series of detailed insights into both the methodology and supporting analytical choices. Keywords: atomic force

• is common to calculate harmonic quantities such as the storage modulus E′, loss modulus E′′, and loss angle δ [23][24][25]. Each has a physical interpretation, representing the elastic and viscous motion of the material and their magnitudes relative to one another. For example, a material that is

• very stiff will have a high storage modulus and a low loss modulus. Such a sample will tend to store a majority of the applied load within its molecular structure and elastically return most or all of that energy when unloaded. Alternately, a medium that is susceptible to large shear forces (such as

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

• Sabrina Barbosa de Souza Ferreira,
• Gustavo Braga,
• Évelin Lemos Oliveira,
• Jéssica Bassi da Silva,
• Hélen Cássia Rosseto,
• Lidiane Vizioli de Castro Hoshino,
• Mauro Luciano Baesso,
• Wilker Caetano,
• Craig Murdoch,
• Helen Elizabeth Colley and
• Marcos Luciano Bruschi

Beilstein J. Nanotechnol. 2019, 10, 2304–2328, doi:10.3762/bjnano.10.222

Outstanding chain-extension effect and high UV resistance of polybutylene succinate containing amino-acid-modified layered double hydroxides

• Adam A. Marek,
• Vincent Verney,
• Christine Taviot-Gueho,
• Grazia Totaro,
• Laura Sisti,
• Annamaria Celli and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 684–695, doi:10.3762/bjnano.10.68

• sweeps from 0.1 to 100 rad s−1 and the gap between plates set at 1 mm. In all cases, the oscillatory shear stress amplitude was checked to ensure that measurements were performed inside the linear viscoelastic domain. The storage modulus (G’), loss modulus (G”) and tan δ (ratio of G” and G’) were

• composites were recorded via the storage modulus (E′) and tan δ, which is the ratio of the loss modulus to the storage modulus (Figure 8). With respect to PBS, the composites present moderate enhancement in the storage modulus E’ over almost the entire temperature range, quantifiable as 6–12% and 17–26% from

• low temperature (−130 °C) up to RT, respectively. More detailed, at room temperature, the increase in E’ is 26% for PBS–LDH/PHE, 20% for PBS–LDH/HIS and 17% for PBS–LDH/nitrate. The larger storage modulus with respect to PBS for such composites indicates a mechanical reinforcement of the matrix due to

Graphene–graphite hybrid epoxy composites with controllable workability for thermal management

• Idan Levy,
• Eyal Merary Wormser,
• Maxim Varenik,
• Matat Buzaglo,
• Roey Nadiv and
• Oren Regev

Beilstein J. Nanotechnol. 2019, 10, 95–104, doi:10.3762/bjnano.10.9

• graphite-containing composites to higher volume fractions of the filler compared to those of GNP-loaded composites [41][48][49][50], in line with previously studied silicone rubber systems [41]. The viscoelasticity of a composite may be described by the dynamic moduli, G' (storage modulus) and G'' (loss

• ), to the Krieger–Dougherty model (Equation 2). The dashed lines in (b) represent the critical volume fraction, φM, found by fitting to the Krieger–Dougherty (K–D) model (Equation 2). Some error bars are hidden by the data symbols due to small measurement errors. Storage modulus (G', solid symbols) and

Layered calcium phenylphosphonate: a hybrid material for a new generation of nanofillers

• Kateřina Kopecká,
• Ludvík Beneš,
• Klára Melánová,
• Vítězslav Zima,
• Petr Knotek and
• Kateřina Zetková

Beilstein J. Nanotechnol. 2018, 9, 2906–2915, doi:10.3762/bjnano.9.269

• (CaPhP_exf_0.5). In the temperature range from 0 °C to 45 °C the exfoliated particles increase the storage modulus compared to that of the pristine epoxy matrix, while the unexfoliated filler decreases it (see Figure 9). For the 0.5 wt % load, the glass transition temperature of the composite films is shifted to

A robust AFM-based method for locally measuring the elasticity of samples

• Alexandre Bubendorf,
• Stefan Walheim,
• Thomas Schimmel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 1–10, doi:10.3762/bjnano.9.1

• distribution of the elastic modulus for each map in Figure 6b and Figure 7b. Because polymers are viscoelastic materials, the elastic modulus Eeff,meas measured on the investigated samples in dynamic mode corresponds to the storage modulus. As the measured contact resonances are quite large compared to the

• inverse of typical material relaxation time, we can assume that the measured storage modulus is independent on the frequency. The measurements yielded values in the range of the Young’s moduli of bulk LLDPE, PP and PS as seen in Table 3. The investigation also evidenced regions of different elastic moduli

• , as seen in the histograms of LLDPE, PP and the SAM: LLDPE shows three different peaks centered at 362, 380 and 393 MPa, PP shows two peaks centered at 1.468 GPa and 1.565 GPa and the SAM shows two peaks centered at 472 and 478.5 MPa. Finally, the value of the storage modulus of FDTS gives an estimate

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• by Equation 6. Integration yields an expression of energy dissipated per fundamental tapping cycle in terms of the viscoelastic material parameters: where the relations and were used. Also, has been substituted for clarity. The first term in Equation 30 is proportional to the storage modulus G′(ω

• case of DMA (see Equation 11), in which the virial is only proportional to the storage modulus. Here, as for the case of dissipated energy, the virial has contributions that are not only proportional to the storage modulus G′(ω), but also to the loss modulus G″(ω), the relaxation modulus G(t) (4th term

• symbols show the analytical calculation based on Equation 30, which closely follows the results obtained from the simulation. The analytical solution specifically gives the amount of dissipated energy that is proportional to the storage modulus (first term in Equation 30, diamond symbols), the amount of

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites

• Claudio Larosa,
• Niranjan Patra,
• Marco Salerno,
• Lara Mikac,
• Remo Merijs Meri and
• Mile Ivanda

Beilstein J. Nanotechnol. 2017, 8, 2026–2031, doi:10.3762/bjnano.8.203

• used p-xylene and dichloromethane solvent to mix MWCNTs and prevent their agglomeration induced by strong van der Waals forces. Previous work carried out on PC/MWCNT composites with focus on the mechanical properties showed an increase in the storage modulus obtained from indentation measurements at

Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications

• Bertha T. Pérez-Martínez,
• Lorena Farías-Cepeda,
• Víctor M. Ovando-Medina,
• José M. Asua,
• Lucero Rosales-Marines and
• Radmila Tomovska

Beilstein J. Nanotechnol. 2017, 8, 1328–1337, doi:10.3762/bjnano.8.134

• in an augmentation of the storage modulus (i.e., stiffness) over the entire temperature range. In addition, the loss modulus of the composites was also higher than that of the blank polymer (Figure 4b), namely the energy dissipation as heat was promoted. This may be due to an additional energy

• . Continuous lines are a guide to the eye. SEM images of the fractured surface of films made of MMA/BA/HEMA/MWCNT in situ hybrid latexes at different air-sonicated MWCNT loadings: (a) 0.1 wt % MWCNT; (b) 0.5 wt % MWCNT; (c,d) 1 wt % MWCNT under different magnifications. (a) Storage modulus and (b) loss modulus

Bio-inspired micro-to-nanoporous polymers with tunable stiffness

• Julia Syurik,
• Ruth Schwaiger,
• Prerna Sudera,
• Stephan Weyand,
• Siegbert Johnsen,
• Gabriele Wiegand and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 906–914, doi:10.3762/bjnano.8.92

• regime by dynamic flat-punch indentation. Interestingly, the storage modulus was observed to increase with increasing pore-area fraction. Conclusion: This outcome appears counterintuitive at first sight, but can be rationalized by an increase of the pore wall thickness as determined by our quantitative

• storage modulus; Introduction Functional adaptation through porous structures is widely present in nature [1]. Natural structures are often made of hierarchical porous networks, serving mainly for passive mechanical functions [1][2][3], but also for capillary channels and membranes [1]. Nature offers

• is subjected to inhomogeneous pressure and/or temperature conditions during steps (ii) and (iii), the pore size within the polymer can vary [20]. To the best of our knowlegde, the correlation between the density of the porous material and its storage modulus, especially the size-dependent mechanical

Nanoscale effects in the characterization of viscoelastic materials with atomic force microscopy: coupling of a quasi-three-dimensional standard linear solid model with in-plane surface interactions

• Santiago D. Solares

Beilstein J. Nanotechnol. 2016, 7, 554–571, doi:10.3762/bjnano.7.49

• only in methods such as CR-AFM or FMOD-AFM [2][3][4][5][6][21]. Therefore, neither the use of the complex modulus nor of quantities derived from it (e.g., the loss tangent, which is the ratio of the loss modulus to the storage modulus) are appropriate for analysis of intermittent-contact AFM

• equal to the storage modulus (the loss modulus is zero, so the complex modulus is real), which according to Equation 17 is equal to k1 and is called the rubbery modulus [25]. At infinite frequency the loss modulus also becomes zero and the complex modulus is again real and reduces to the storage modulus

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• -resonance spectra are used to calculate the contact stiffness k* and the local contact damping E″/E′ by employing suitable models for the tip–specimen contact, and in turn enabling one to image and to measure the local elasticity or the storage modulus E′ and the damping or loss modulus E″ of the specimen

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• CTAB coated rods suggesting an increase in acoustic load corresponding to a larger stiffness (storage modulus). Keywords: atomic force microscopy; CTAB; gold nanorods; membrane tension; MDCK II cells; QCM; Introduction The interest in gold nanoparticles (NP) for biomedical applications in the field

Frequency, amplitude, and phase measurements in contact resonance atomic force microscopies

• Gheorghe Stan and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 278–288, doi:10.3762/bjnano.5.30

• acoustic microscopy (AFAM) configuration [3]), such that the tip oscillation amplitude and its phase with respect to the excitation can be measured and converted into a loss and storage modulus. In contact resonance AFM (CR-AFM) [3][4][5][6][7][8][9] a similar setup is used, supplying the sinusoidal

Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

• Sidney R. Cohen and
• Estelle Kalfon-Cohen

Beilstein J. Nanotechnol. 2013, 4, 815–833, doi:10.3762/bjnano.4.93

• principles in nanoindentation, and compares and contrasts these two techniques as they are used for characterization of viscoelastic processes at the nanoscale. Keywords: atomic force microscopy; loss modulus; nanoindentation; storage modulus; viscoelasticity; Review Introduction Understanding and

• strain could be modulated. In this case, stress and strain will exhibit a phase difference designated as angle δ and the modulus can be now expressed as complex modulus E*: Here, E′ is the storage modulus, which measures the energy stored during one oscillation cycle, and E″ is the loss modulus, which

• temperature. Concomitantly, the storage modulus is reduced since molecular relaxation loosens the molecular bonds. Experimental aspects of the dynamic response measurement Some caveats should be applied in comparing experiments made under different conditions: The creep response depends on the tip shape, and