Abstract
Dynamic Mechanical Analysis (DMA) is essential for probing the viscoelastic properties of polymers and elastomers, yet conventional bulk DMA is limited to averaged measurements over large volumes. Park Systems’ AFM-based DMA combines the nanoscale resolution of Atomic Force Microscopy with dynamic mechanical testing, enabling localized and quantitative analysis of viscoelastic behavior. In a polystyrene–low density polyethylene (PS–LDPE) blend, the combined use of PinPoint nanomechanical mode and AFM-based DMA revealed domain-specific contrasts in stiffness, deformation, adhesion, and loss tangent. For styrene–butadiene rubber (SBR), temperature-controlled AFM-based DMA enabled stable measurements down to –3 °C and construction of a master curve via time–temperature superposition, extending predictive insight across broad frequency and temperature ranges. These results show that Park Systems’ AFM-based DMA is a powerful and practical approach to connect nanoscale heterogeneity with viscoelastic performance relevant to real applications. This unique temperature-dependent capability supports the development of high-performance polymers and elastomers for use in tires, seals, and electronic components.
Introduction
Atomic Force Microscopy (AFM)-based Dynamic Mechanical Analysis (DMA) is an advanced technique that enables the measurement of nanoscale viscoelastic properties of materials. By combining the high spatial resolution of AFM with the quantitative mechanical testing capability of conventional DMA, researchers can probe localized mechanical and viscoelastic behavior with nanometer-scale precision¹².
This approach is particularly crucial for materials such as polymers, nanocomposites, thin films, and biological specimens, where local mechanical variations can strongly influence macroscopic properties and the performance of polymer-based products such as rubber components, tires, and sealing materials. While traditional DMA offers critical insights into the bulk viscoelastic properties of materials, its spatial resolution is limited to the microscale or larger. In contrast, AFM-based DMA provides the necessary resolution to evaluate heterogeneous structures, surface regions, or thin films that dictate the function of modern engineered materials.
Moreover, temperature control is essential in DMA, as many materials, especially polymers, exhibit strong temperature-dependent transitions (e.g., glass transition)³⁻⁵. Recent advances in Park Systems AFM instrumentation now enable dynamic mechanical measurements extending to sub-zero temperatures, allowing researchers to study material performance in conditions relevant to real-world applications such as tire durability, sealing reliability, and electronic components in cold climates.
Theoretical Background
Park’s DMA is an advanced AFM-based technique that measures local viscoelastic properties with nanometer-scale precision, making it particularly valuable for thin films, biomaterials, and nanocomposites where microstructural variations are critical⁶. Unlike conventional bulk DMA, which provides averaged values over large sample volumes, AFM-based DMA uses an AFM tip to apply a controlled oscillatory force directly to specific regions, enabling localized mechanical mapping.
During measurement, a sharp AFM tip is brought into contact with the sample surface and oscillated at a series of frequencies (Figure 1). The frequency-dependent response of the material is recorded by monitoring cantilever deflection and phase lag. These parameters allow for the direct calculation of local loss tangent (tan δ), a key parameter describing viscoelastic behavior.
A unique strength of AFM-based DMA is the ability to construct a "master curve." By applying the principle of time–temperature superposition, data collected over a range of temperatures can be shifted along the frequency axis to create a unified curve. This enables prediction of long-term viscoelastic responses and material performance under conditions outside the directly measured window, such as very high frequencies (fast stress) or very low temperatures (slow, aging processes). This will be illustrated in Case Study 2 of this note.
Figure 1. Schematics of Park Systems AFM-based DMA methodology. AFM tip is brought into contact with the sample with a defined preload force (set point). The tip is oscillated while sweeping the modulation frequency, allowing measurement of viscoelastic response through cantilever deflection and phase lag.
Case Study 1: Mechanical and Viscoelastic Mapping of PS-LDPE
A quantitative analysis of nanoscale mechanical and viscoelastic properties was conducted on a Polystyrene-Low density Polyethylene (PS-LDPE) blend using AFM methods. The same region of the sample surface was examined with both PinPoint nanomechanical mode and AFM-based DMA, enabling a direct comparison of local properties across PS and LDPE domains.
PinPoint nanomechanical mapping provided high-resolution images of surface topography, deformation, Young’s modulus, and adhesion energy⁷⁸. The topography revealed distinct phase-separated domains, with PS forming island-like structures within the continuous LDPE matrix. Mechanical property mapping showed clear contrasts, as PS regions exhibited higher stiffness and lower deformation compared with LDPE, consistent with their known bulk properties. Young’s modulus in PS domains reached several GPa, whereas LDPE values were typically below 1 GPa. Adhesion mapping further indicated stronger adhesive interactions in LDPE areas, reflecting greater molecular mobility and chain flexibility relative to the rigid PS domains.
In contrast, AFM-based DMA enabled quantitative mapping of viscoelastic behavior through the local loss tangent (tan δ). The loss tangent maps closely followed the phase morphology: PS domains showed lower tan δ values indicative of predominantly elastic behavior, while LDPE exhibited significantly higher tan δ values, pointing to pronounced viscoelasticity and energy dissipation. These findings confirmed that LDPE domains undergo greater molecular rearrangement and damping under oscillatory loading, whereas PS remains relatively rigid and non-dissipative.
The complementary results from PinPoint and AFM-based DMA provided consistent and spatially resolved insights into polymer heterogeneity. Distinct property boundaries were clearly observed in both mechanical and viscoelastic maps, demonstrating how the combined techniques enable comprehensive nanoscale characterization of polymer blends.
Figure 2. Complementary Nanomechanical and Viscoelastic Mapping of PS–LDPE. (a) PinPoint nanomechanical images of PS–LDPE showing surface topography, deformation, Young’s modulus, and adhesion energy. (b) Corresponding AFM-based DMA loss tangent map of the same region, highlighting local variations in viscoelasticity between PS (lower tan δ) and LDPE (higher tan δ) domains.
Case Study 2: Low-temperature AFM-based DMA and master curve construction in SBR
The mechanical properties of polymers and elastomers such as Styrene–Butadiene Rubber (SBR) change markedly with temperature, with viscoelastic behavior strongly affected as the material is cooled⁹. SBR, widely used in products like tires, seals, and gaskets, must maintain reliable performance across varying environmental conditions, especially in sub-zero climates. At low temperatures, SBR undergoes a glass transition at glass transient temperature (Tg), shifting from a flexible rubbery state to a rigid brittle one, which directly impacts the safety and functionality of SBR-based products, particularly in maintaining tire flexibility and grip on icy roads.
To investigate this behavior, AFM-based DMA was performed with Park Systems’ Temperature Control Stage (TCS), which allowed precise regulation of the sample temperature (Figure 3b). To prevent condensation on both the sample and the AFM probe, the experiments were carried out in a controlled glovebox with actively maintained oxygen and humidity levels (Figure 3a). This unique combination of sub-zero temperature control and environmental stability is a key strength of Park Systems’ AFM-based DMA, enabling reliable viscoelastic characterization under conditions that are extremely challenging for conventional AFM systems.
Figure 3. Low-temperature DMA Setup with Controlled Glovebox and Temperature Control Stage. (a) Park Systems AFM integrated in a controlled glovebox for sub-zero temperature measurements, preventing condensation effects. (b) Temperature Control Stage (TCS) setup inside the AFM showing sample mounting and environmental controls for precise low-temperature DMA experiments.
Loss tangent (tan δ) was measured on SBR at five temperatures: –3 °C, 5 °C, 10 °C, 22 °C, and 25 °C (Figure 4). The data revealed a pronounced shift in viscoelastic response with decreasing temperature, with the glass transition clearly observed. By applying time–temperature superposition, frequency sweeps collected at different temperatures were combined into a continuous master curve spanning a broad frequency range. This approach enabled extrapolation of material behavior well beyond the limits of direct measurement.
Importantly, the AFM-based DMA master curve constructed at sub-zero temperatures showed excellent agreement with the reference bulk DMA curve at 20 °C (blue line in Figure 4). This correlation validates the accuracy of AFM-based DMA and demonstrates its capability to reproduce bulk-level viscoelastic trends at the nanoscale. Such consistency confirms that nanoscale measurements can be directly related to conventional macroscopic results, while also extending the accessible range of conditions. This capability is particularly valuable for applications requiring flexibility, damping, and mechanical integrity in extreme cold. Mapping the master curve under such conditions is therefore critical for developing SBR formulations with assured performance in winter environments, highlighting Park Systems’ unique advantage in temperature-dependent DMA at the nanoscale.
Figure 4. Loss tangent as a function of DMA modulation frequency measured on SBR at various temperatures (–3 °C, 5 °C, 10 °C, 22 °C, 25 °C). Master curve construction via time–temperature superposition extends the viscoelastic profile beyond the directly measured range, showing strong consistency with bulk DMA master curve at 20 °C (blue line).
Conclusions
Park Systems’ AFM-based DMA technology enables nanoscale, site-specific characterization of viscoelastic properties, providing a clear advantage over conventional bulk DMA that only yields averaged responses. This capability is especially valuable for polymers and elastomers, where localized structures strongly influence overall performance.
In the PS–LDPE blend, combining PinPoint nanomechanical mode with AFM-based DMA produced complementary maps of elastic and viscoelastic properties, clearly distinguishing domain-specific differences in stiffness, deformation, and adhesion. In the SBR study, sub-zero temperature-controlled AFM-based DMA enabled precise viscoelastic measurements down to –3 °C. By applying time–temperature superposition, a master curve was successfully constructed, extending predictive insight beyond the directly measured ranges.
These results demonstrate that AFM-based DMA, when paired with advanced environmental control such as glovebox integration and low-temperature stages, is a powerful tool for understanding and engineering material behavior under extreme conditions. This approach provides critical information for developing high-performance polymers and elastomers used in automotive tires, seals, and electronic components, where mechanical reliability and damping must be assured across diverse environments.
Park Systems’ AFM-based DMA thus establishes a practical and reliable path to connect nanoscale heterogeneity with application-relevant viscoelastic performance, setting a new standard for temperature-dependent DMA measurements at the nanoscale.
Acknowledgements
The authors gratefully acknowledge the invaluable support and collaboration of Professor Ken Nakajima and his research group at Tokyo Institute of Technology. Their expert guidance in the selection of representative polymer blend samples, including PS–LDPE and SBR, was instrumental to this study. The provided samples, together with the generous access to their laboratory facilities for conducting AFM-based DMA measurements, significantly contributed to the quality and depth of the experimental work. We also appreciate their thorough data analysis and insightful feedback throughout the research process, which greatly enhanced the rigor and clarity of this application note.
References
1. Nakajima, K., Ito, M., Nguyen, H. K., & Liang, X. (2017). Nanomechanics of the rubber–filler interface. Rubber Chemistry and Technology, 90(2), 272-284.
2. Nguyen, H. K., Liang, X., Ito, M., & Nakajima, K. (2018). Direct mapping of nanoscale viscoelastic dynamics at nanofiller/polymer interfaces. Macromolecules, 51(15), 6085-6091.
3. Chartoff, R. P., Menczel, J. D., & Dillman, S. H. (2009). Dynamic mechanical analysis (DMA). Thermal analysis of polymers: fundamentals and applications, 387-495.
4. Menard, K. P., & Menard, N. R. (2002). Dynamic mechanical analysis in the analysis of polymers and rubbers. Encyclopedia of polymer science and technology, 1-33.
5. Deng, S., Hou, M., & Ye, L. (2007). Temperature-dependent elastic moduli of epoxies measured by DMA and their correlations to mechanical testing data. Polymer testing, 26(6), 803-813.
6. https://www.parksystems.com/en/products/research-afm/AFM modes/Nanomechanical-Modes/dynamic-mechanical-analysis1
7. https://www.parksystems.com/en/products/research-afm/AFM modes/Nanomechanical-Modes/pinpoint--afm-nanoelectrical-modes
8. https://youtu.be/z5F8-18of_I?si=bThIehyXR-GHMu71
9. Chen, C., He, C., Bai, T., Hu, Z., & Fan, Z. (2025). Influence of Rubber
