Hard Domains Research Articles

Improving the Mechanical Properties and Tribological Behavior of Sulfobetaine Polyurethane Based on Hydrophobic Chains to Be Applied as Artificial Meniscus.

In the context of meniscus reconstruction in knee joints, current bulk biomaterials fail to meet the clinical demands for both excellent mechanical strength and low coefficient of friction. In this research, zwitterionic polyurethanes (PUs) with varying sulfobetaine (SB) groups were synthesized as the potential materials for artificial meniscus to investigate the relationship between the structures of SB groups and the performances of PUs. Under the saturation condition of 3 mg/mL hyaluronic acid aqueous solution, PU with long-alkyl chains and SB groups (PU-hSB4) exhibited a good tensile modulus (111.5 MPa) because the hydrophobic interaction of carbon chains was able to maintain the ordered aggregations of hard segment domains. Interestingly, hydrophobic chains in the molecular chain could also improve the tribological performance of PU-hSB4 instead of resulting from the surface roughness of samples, the components of lubricants, and the counterface of samples. A thicker and relatively stable hydration layer of noncrystal water was formed on the surface of PU-hSB4, which exhibited superior resistance to external forces compared to other PUs. Even if the hydration layer was damaged, PU-hSB4 was able to resist the compression of cartilage due to its high surface modulus, thus maintaining a similar and stable coefficient of friction (0.15-0.16) to native meniscus (0.18) and excellent wear resistance. In addition, the low cytotoxicity of PU-hSB4 further demonstrated its great potential to be applied in artificial meniscus instead.

Aromatic disulfide-induced self-reinforcing polyurethane elastomer with self-healability

Developing new strategies to improve the mechanical robustness of self-healing polymer materials to meet engineering requirements remains a great challenge and research focus. Herein, a self-reinforcing strategy of self-healing polyurethane (PU) elastomer is presented to achieve simultaneous giant tensile strength (33.3 ± 1.7 MPa) and toughness (141.9 ± 3.7 MJ m−3). Two chain extenders, diethyl 2,2-bis(hydroxymethyl)malonate (BDMH) and bis(4-hydroxyphenyl) disulfide, are elaborately regulated in the molecular structure to balance the mechanical and self-healing properties. On the one hand, BDMH containing abundant ester groups provide a large number of hydrogen bond (H-bond) acceptors. On the other hand, the incorporation of aromatic disulfide forms reversible hierarchical H-bonds confined to loosely-stacked hard domains and improves the physical crosslinking density, thus realizing the self-reinforcing of PU elastomer based on the strain-induced crystallization (SIC) of polytetramethylene ether glycol (PTMEG) as the soft segment. Hierarchical H-bonds with dynamic nature acting as sacrificial bonds can dissociate and regenerate and dissipate a large amount of energy, thus contributing to mechanical robustness and self-healing properties. In addition to constructing a self-healing PU elastomer with mechanical robustness, a remarkable progress over previous work is that we perform fundamental study at the molecular level and reveal the three-stage evolution of H-bonds and aggregation structure during stretching, thus revealing the SIC behavior and mechanism, which provides a theoretical basis for the strengthening and toughening of self-healing PU elastomer.

Structure-property relationship in vanadium micro-alloyed TRIP steel subjected to the isothermal bainite transformation process

Structure-property relationship in vanadium micro-alloyed TRIP steel is investigated focusing on austenite transformation, precipitation behavior and mechanical performance. Microstructural evolution of the steel during processing was characterized mainly using EBSD, TEM and APT techniques; and its influence on mechanical properties was discussed. The TRIP steel exhibits complex microstructure including intercritical ferrite (IF), bainitic ferrite (BF), retained austenite (RA) and martensite. After identical intercritical annealing (IA), IF fraction keeps constant, BF and RA fractions increase while martensite fraction decreases with decreasing isothermal bainite transformation (IBT) temperature from 470 to 380 °C. The initially precipitated vanadium carbides (VC) in the hot-rolled specimen undergo coarsening during IA process, accompanied with some newly precipitated VC in either ferrite or in austenite, confirmed by the co-existence of small-sized and coarsened VC after IA process, as well as occurrence of K–S orientation relationship between VC and the α-Fe matrix. Ultra-fine average grain size of less than 1 μm in the TRIP heat-treated steel is achieved by the refining effect of these nano-scale VC precipitates, which can inhibit phase boundary (PB) migration during IA process and promote bainite transformation during subsequent IBT process. The higher volume fraction of RA accompanied with higher carbon enrichment intensifies sustainable strain hardening and finally increased ductility of the specimens treated under lower IBT temperature. In the IBT-380 specimen with the highest RA and BF fractions, the occurrence of micro-yielding phenomenon is a result of the Cottrell atmosphere in soft domain BF and stress relaxation due to RA to martensite transformation, during which the soft domain IF/RA/BF and hard domain martensite yields step by step. An excellent mechanical performance is thus achieved in the IBT-380 specimen, meeting the requirements for the 3rd generation advanced auto-steel.

Understanding water absorption effect on molecular dynamics, microstructures and relaxation behavior of segmented polyurethane elastomers

The influence of water absorption on molecular dynamics, microstructures and relaxation behaviors of polyurethane (PU) elastomers with polyether (poly(tetramethylene glycol), PTMG) soft segments has been studied. Kinetics of water absorption of PU elastomer can be well fitted by Fick's model. However, non-Fickian absorption behavior was observed in the late stage at 60 °C, which was presumed to be related to the plasticization of some hard domains. Broadband dielectric relaxation spectroscopy was used to investigate the molecular dynamics of PU elastomers. The analysis of α-relaxation and Maxwell-Wagner-Sillars interfacial polarization indicated that the water absorption has a great influence on the molecular mobility of soft segment and the interface regions between soft domains and hard domains. Microphase separation structures of PU elastomers consisted of loose, partially regular and compact hard domains. Water molecules could interact with loose hard domains and lead to the plasticization. The results of stress relaxation behavior indicated that water absorption leaded to remarkable increase in the stress relaxation ratio. The deterioration of relaxation properties caused by water absorption was not only related to the soft segments, but also caused by the plasticization of the interface regions and the hard domains.

Transparent self-healing luminescent elastomer with superior stretchability achieved via dynamic hard domain design

High mechanical performance versatile materials exhibiting rapid self-healing and luminescence ability are highly desired and present tremendous prospects in various fields. However, it is still a huge challenge to concurrently integrate all the above capacities into individual polymer materials, since these capabilities stem from different molecular mechanisms. Here, a dynamic hard domains strategy is reported for fabricating transparent luminescent self-healing elastomers featuring unprecedented stretchability (4333 ± 36%), high toughness (42.25 ± 0.19 MJ m−3) enabled by hydrogen-bonding (single and double) and lanthanide-bipyridine (Ln-Bpy) coordination interactions in the polymer chains. The dynamic rigid domains containing hydrogen-bonds constructed by urea and urethane groups and Ln-Bpy coordination also lead to a very dynamic system for fast self-healing at room temperature. Besides, excellent luminescence performance was obtained via the efficient energy transfer from the Bpy component to Ln3+ (Eu3+ and /or Tb3+). This strategy of dynamic rigid domains as building blocks applied in this study provides an alternative approach for preparing self-healing luminescence materials with superior stretchability and high toughness.

Bioinspired ultra-tough, exceptionally stretchable, and self-recoverable bio-based coating for visual damage detection and self-healing

Developing intelligent materials with integrated ultra-high-performance damage monitoring and repair functions is of paramount significance for broadening the application of the latest generation of smart materials. Here, inspired by spider silk and biological skin, we embedded multiple hydrogen bonding motifs and rigid alicyclic groups with attached damage monitoring sensors in bio-based polyurethanes to create bio-based elastomers with exceptional mechanical properties combined with repair and damage monitoring functionalities. Benefiting from the abundance of multiple hydrogen bonding elements within the polyester backbone for fracture and remodeling as external energy dissipation, and the contribution of asymmetric alicyclic groups embedded in hard domains. The elastomer possesses exceptional toughness (583 MJ·m−3) and tensile strength (43 MPa), the elongation at break point is 2600 %, and self-healing (86 % at 60 °C for 6 h), environmental adaptability, and recyclability, thereby achieving the preparation of ultra-tough self-healing elastomeric materials. Simultaneously, the internally embedded sensors enable the localization and monitoring of damage through visually observable means, such as quenching and discoloration. The elastomer recovers well in 3.5 wt% NaCl solution and provides corrosion protection (9.23 × 107 Ω·cm2 even after 50 days of immersion), achieving the integration of ultra-high mechanical performance coating materials with damage warning and repair functions. Therefore, the molecular structure design scheme of the biomimetic elastomer provides constructive guidance for surface protection application of engineering equipment in service under harsh environments.

Tailoring strength and ductility of Mg97Y2Zn1 alloy through the architecture of heterogeneous lamellar structure by large-ratio hot extrusion

In this study, a heterogeneous lamellar structure is achieved in Mg97Y2Zn1 alloy via large-ratio hot extrusion of the alloys in as-cast (CE) and as-annealed (AE) stages. The ultimate tensile strength (UTS) of CE and AE alloys is 426.5 and 471.4 MPa, and their fracture elongation (FE) is 8.1% and 1.0%, respectively. Mechanical properties of the CE and AE alloys exceed that of the majority of wrought Mg97Y2Zn1 alloys due to the heterostructure induced strengthening. Both in the two extruded alloys, α-Mg layers and LPSO layers acting as soft and hard domains, respectively, constitute the heterogeneous lamellar structure. As a result of the narrower spacing of α-Mg and LPSO layers, more refined DRX grains and LPSO particles, and the increased volume fraction of LPSO phase, the strength of the AE alloy is higher than that of CE alloy. However, the AE alloy exhibits poor ductility owing to the easy aggregation of dislocations and stress at the interfaces of narrower layers. Based on discussion of the strengthening mechanisms, the preparation of Mg97Y2Zn1 alloys with tailored mechanical properties of high UTS ranging from 420 to 480 MPa, and FE 1~ 8%, could be realized via the combination of annealing (controlling the content of 14H phase) and large-ratio hot extrusion (promoting the formation of heterogeneous lamellar structure).

Ambient Environment Adaptive Elastomer Constructed by Microphase Separation and Segment Complexation of Triblock Copolymers.

Elastomers with environmental adaption have attracted considerable attention for advanced applications in various areas. Here, we fabricate an ambient environment adaptive elastomer by assembling triblock copolymers polystyrene-b-poly(acrylic acid)-b-polystyrene (SAS) and polystyrene-b-poly(ethylene oxide)-b-polystyrene (SES). Owing to the microphase separation of triblock polymers and hydrogen-bonding complexation of their middle segments, the SAS/SES complex presents dichotomy of vitrified hard PS domains and soft PAA/PEO domains, which presents major relaxation transition in the temperature zone 10-30 °C and relative humidity (RH) 40-60%. The SAS/SES elastomer presents quick adaption to the ambient environment change with temperature and humidity coupling. Moreover, after a loading-unloading cycle training, the SAS/SES elastomer exhibits domain orientation, low energy dissipation, high recovery ratio, and distinct strain stiffening compared with the pristine complex. The SAS/SES elastomer has potential to be used as a sensing and adaption component for complicated intelligent systems.

Bioinspired Conductive Enhanced Polyurethane Ionic Skin as Reliable Multifunctional Sensors.

Ionogels prepared from ionic liquid (IL) have the characteristics of nonevaporation and stable performance relative to traditional hydrogels. However, the conductivities of commonly used ionogels are at very low relative to traditional hydrogels because the large sizes of the cation and anion in an IL impedes ion migration in polymer networks. In this study, ultradurable ionogels with suitable mechanical properties and high conductivities are prepared by impregnating IL into a safe, environmentally friendly water-based polyurethane (WPU) network by mimicking the ion transport channels in the phospholipid bilayer of the cell membrane. The increase in electrical conductivity is attributed to the introduction of carboxylic acid in the hard segment of WPU; this phenomenon regularly arranges hard segment structural domains by hydrogen bonding, forming ionic conduction channels. The conductivities of their ionogels are >28-39 mS cm-1 . These ionogels have adjustable mechanical properties that make the Young's modulus value (0.1-0.6MPa) similar to that of natural skin. The strain sensor has an ultrahigh sensitivity that ranges from 0.99 to 1.35, with a wide sensing range of 0.1%-200%. The findings are promising for various ionotronics requiring environmental stability and high conductivity characteristics.

Preparation of Robust, Room‐Temperature Self‐Healable and Recyclable Polysiloxanes Based on Hierarchical Hard Domains

The contradiction between high mechanical strength and mild healing conditions has long existed in self‐healing materials, which limits the application of self‐healing materials. The preparation of robust materials with excellent healing performance under mild conditions can effectively reduce resource waste and environmental pollution. Herein, self‐healing polysiloxane elastomer materials, APDMS‐MDI‐IPDI‐Bs, based on microphase separation strategy are reported. Through the synergistic effect of the designed urea hydrogen bond and the nitrogen‐coordinated boroxine structure, the materials can maintain high mechanical properties (maximum tensile strength up to 3.35 MPa, elongation at break up to 316%), while maintaining excellent self‐healing and recyclable ability (24 h healing efficiency at room temperature can reach 94.77 ± 3.23%), and the performance can be repeated many times without decay. APDMS‐MDI‐IPDI‐Bs also exhibit unique hydrophobicity, expanding the application scenarios of materials containing boroxine structure.

Synthesis and properties of water‐dispersible polyurethanes based on various diisocyanates and PEG as the hard segment

AbstractWater‐dispersible polyurethanes are a greener alternative to polyurethane solutions in organic solvents. Various polyurethane materials were prepared by a two‐step polymerization procedure of polypropylene glycol with Mn of 2000, polyethylene glycol with Mn of 1500, and diisocyanates with different chemical structures, aliphatic, cycloaliphatic and aromatic. It was investigated how the diisocyanate structure affected the molecular morphology, contact angle measurements, and physical characteristics of water‐dispersible polyurethanes. FTIR and NMR measurements showed a close relationship between the intermolecular connections and the hard segment structure, mainly of the diisocyanate used. Also, the polarized light method showed that the presence of the PEG in the hard domain improved aggregation through physical interactions due to its structural flexibility and mobility. These water‐dispersible polyurethanes can assure the use of these polyurethane materials in a broad range of applications with increased environmental protection.

Simultaneously enhancing strength and ductility of HCP titanium via multi-modal grain induced extra dislocation hardening

According to Considère necking criterion, enhancing strength of a material will decrease its elongation to failure, i.e. ductility, even if the strain hardening rate remains unchanged. Unfortunately, four traditional strengthening mechanisms including grain refinement, deformation, solid solution and 2nd-phase particle strengthening increase the yield strength by increasing the critical shear stress for slip initiation and unexceptionally reduce the strain hardening ability and ductility. Recent experiments revealed that implementation of heterostructures can produce extra hetero-deformation induced (HDI) hardening and thus reduce ductility loss while enhancing strength. However, the improved ductility was still less than that of coarse-grained counterparts. Here we fabricated a bulk heterostructured Ti with a uniform multi-modal grain size distribution in which the single individual micro-grain is surrounded and constrained by three-dimensional ultrafine grains. Tensile tests revealed the multi-modal Ti has a high yield strength of 800 MPa, ductility of 28.5%, and outstanding HDI hardening effect compared with its coarse-grained counterparts (a yield strength of 550 MPa and ductility of 26.5%). These mechanical properties of our multi-modal Ti are also superior to other literature reported data of heterostructured Ti. Microstructural characterization further reveals the uniform distribution between hard and soft domains produces maximum interface density and HDI hardening effect. Moreover, the HDI causes extra 〈c + a〉 geometrically necessary dislocations piling ups in the constrained micro-grains, which produce enough and extra strain hardening to maintain and even enhance slightly the ductility. Our work provides a strategy to simultaneously enhance strength and ductility of metals via enough and extra strain hardening capability increase.

4D Printed Thermoplastic Polyamide Elastomers with Reversible Two‐Way Shape Memory Effect

Abstract4D printing has become a research hotspot in recent years. Only a few elastomer materials can be printed by selective laser sintering (SLS) and achieve a reversible two‐way shape memory effect (2W‐SME) at the same time, which greatly limits the applications of 4D printing. Therefore, it's still a challenge to develop a new elastomer possessing reversible 2W‐SME. In this work, a series of thermoplastic polyamide elastomers (TPAEs) are synthesized successfully through the polycondensation reaction of PA1212 prepolymer and polyetheramine, which exhibited excellent thermal stability, flexibility, and resilience. The crystalline PA1212 hard domains acted as a skeleton to maintain the permanent shapes, and the polyether soft segments acted as actuation phase to realize crystallization‐induced elongation (CIE) and melting‐induced contraction (MIC) under internal stress. The reversible 2W‐SME of T0.6‐2 films is first realized, and the reversible response strain can reach 15.2% and a good shape recovery ratio is also achieved. After freeze‐crushing and sieving, SLS‐printable TPAE powder is obtained, and the SLS‐processed samples also exhibited excellent reversible 2W‐SME to realize 4D printing. This new TPAE material not only broadens 4D printable materials, but also has a potential in the fields of soft robots, temperature sensors, and even aerospace equipment.

Simultaneous Configuration of High Room-Temperature Self-Healing Efficiencies and Tough Mechanical Properties of Energetic Adhesives for Energetic Composites

Room-temperature self-healing adhesives require more flexible polymer chains and weaker interactions, which are not conducive to good mechanical properties. Therefore, an energetic self-healing adhesive containing asymmetric alicyclic structures and multiple urea groups was designed. The asymmetric alicyclic structures could form loosely packed hard domains, and the irregular arrangement of multiple continuous urea groups could strengthen the physical cross-linking and improve the strengths of the hard domains. As a result, adhesives with improved mechanical properties (tensile strength and toughness) were obtained, and their dynamic adaptabilities and responsiveness required for self-healing at room temperature were maintained. The glycidyl azide polymer-based polyurethane (GPU) adhesive (GPU-3.0) exhibited excellent comprehensive performance in terms of toughness, healing efficiency, adhesion strength, and energy level. The maximum tensile strength and toughness of the energetic composite material (ECM, GPU/Al) prepared using GPU-3.0 and Al were 2.52 MPa and 2.45 MJ m–3, respectively. After 72 h at room temperature, the scratches on the GPU/Al surface were no longer observed and the mechanical properties were completely recovered. Therefore, the designed adhesive, which displays a high-efficiency room-temperature self-healing capacity and good mechanical properties, is applicable in self-healing ECM systems. This strategy should provide insights for use in improving the stabilities and safety of ECMs.

Domain wall state diagram for SrTiO3/BaTiO3 superlattice structures

The domain wall structure of ferroelectric/ paraelectric superlattices can be much more complex due to the influence of the superlattice stacking structure, the in-plane strain induced by the substrate and environmental temperature. In this study, we employed a phase field model to investigate the domain wall state of the SrTi[Formula: see text]/BaTi[Formula: see text] superlattice structure. The domain wall thickness for the SrTi[Formula: see text]/BaTi[Formula: see text] layer was measured using a hyperbolic function. Based on the simulation results, here, we show a domain wall state diagram to distinguish the hard and soft domain states. The polarization profiles across hard/ soft domain walls were illustrated and analyzed. Our simulation results offer a useful concept for the control of the domain wall state in the ferroelectric superlattice.

Effect of warm-rolling on microstructure and superior mechanical properties of a cost-effective AlCrFe2Ni2 high entropy alloy

The possibility of tailoring microstructure and tensile properties of a cobalt-free cost-effective (FCC+B2) AlCrFe2Ni2 high entropy alloys (HEA) was explored in this work. For this purpose, the HEA was warm-rolled at 400 °C, 600 °C, and 750 °C to 90% reduction in thickness and further annealed at different temperatures. The increasing warm-rolling reduction resulted in progressive alignment and microstructural refinement. The HEA warm-rolled at 400 °C revealed a continuous nanoscale lamellar structure as opposed to disrupted and segmented lamellae in the HEA warm-rolled at 600 °C and 750 °C. The BCC fraction increased remarkably after warm-rolling at different temperatures due to the increased stability of the BCC phase. Annealing resulted in transformation to microduplex structures and restoration of the FCC fraction. However, the HEA warm-rolled at 400 °C and annealed at 800 °C showed the development of a heterogeneous microstructure with retained lamellar and partially transformed microduplex regions. The heterogeneous lamellar microstructure resulted in simultaneous improvement in strength and ductility with a yield strength of ∼ 921 MPa and elongation of ∼23%. Thus, the HEA outperformed other cobalt-free HEAs from an integrated cost-performance comparison. Microstructural analysis of the broken tensile specimen indicated that the soft domains were considerably strain-hardened in the presence of the hard domains, leading to synergistic improvement in strength and ductility in the heterostructured HEA.

A micromechanical approach to TPU mechanical properties: Framework and experimental validation

Mechanistic understanding of the mechanical properties of elastomeric thermoplastic polyurethane (TPU) rely on the hard segment content (HSC) as the sole predictor of mechanical properties for a given chemistry, regarding the TPU morphology as a nanocomposite of hard domains in a softer matrix. In order to go beyond this binary view of TPU structure-property relationships, the behavior of the soft segment-rich domain and the interphase between the hard and soft domains should be given more consideration. This work explores the application of several common micromechanical models to a series of TPUs with increasing HSC. A framework to determine model parameters (phase volume and modulus) for TPUs in general was developed. The ability of the model to capture the reinforcement behavior was evaluated in the context of the experimentally determined mechanical properties and morphology. An Eshelby double inclusion (EDI) model was used to compare two and three phase models. The soft matrix modulus, Em, was used as the fitting parameter to match the experimental Young's modulus for a series of TPUs with increasing HSC. The procedure reveals that Em must also increase as a function of HSC to realize the degree of reinforcement found experimentally. The design of TPU for specific applications would greatly benefit from the ability to predict stress-strain behavior from models which represent the complex TPU morphology.

Hydrophilic polyurethane films containing gastrodin as potential temporary biomaterials

Elastomeric polyurethane films containing HDI or IPDI diisocyanate, poly(caprolactone) diol and butane-1,4-diol (BD) or gastrodin (GS) were synthesized in two-step polyaddition reaction. Their chemical structures were confirmed by FTIR and NMR spectroscopy. The phase structure was analyzed by WAXD and DSC methods, confirming the presence of a crystalline phase in the hard domains. The introduction of GS instead of BD results in an increase in the free surface energy of the films (FSE > 40 mJ/m2). The consequence of this is an increase in the water uptake, but at the same time a reduction in resistance to hydrolysis in Baxter's salt solution, as well as increased biodegradability in contact with bacterial strains (Bacillus sp. - gram positive, Pseudomonas sp. - gram negative). PU elastomeric films modified by gastrodin can be applied in tissue engineering films as temporary biomaterials with hydrophilic properties, capable of biodegradation in the body.

Light-Matter Interactions Revealing Load-Induced Phase Mobility in Elastomers.

Elastomers with segmental microstructure are a fascinating class of shock-tolerant and impact-resistant materials. However, their technological potential remains untapped due to a vague understanding of the molecular contributions to their superior mechanical behavior. Herein, in situ light-matter interactions, to reveal the extent of microstructural mobility by temporally exploiting molecular processes during creep response, are leveraged. The segmental microstructure comprises aromatic hard domains embedded within an aliphatic soft matrix. High-resolution digital image correlation reveals the development of strain striations, mild anisotropy, and the mechanisms responsible for domain mobility, where the rate of hard segment mobility is found to be 60% slower than that of the soft segment. Terahertz spectral analyses pinpoint the contributions of interchain hydrogen bonding of the hard segments and their significant conformational changes by observing spectral features at ≈1.2THz and ≈1.67THz. Moreover, the domain mobility is examined using experimental and computational light scattering approaches, uncovering dynamic scattering and elucidating the difference in the complex refractive index of the soft and hard segments. The study unlocks the pathway for quantitative measurements of elusive molecular mobility and conformational changes during mechanical loading and sheds light on the origin of the shock tolerance in some elastomeric polymers with segmental microstructure.

AFM monitoring of the cut surface of a segmented polyurethane unveils a microtome-engraving induced growth process of oriented hard domains

We report on nanoscale order-disorder transitions of hard segments and their domains composed of 4,4′-methylenebis(phenyl isocyanate) - 1,4-butanediol (MDI-BD), in polycaprolactone-based (Mn = 2000 g/mol) polyurethanes (PCL-PUs), when the free surface is pre-oriented by cryo-microtoming of the material. Morphological variations of the hard domains as a function of temperature and the anisotropy of surface morphology features are captured by employing Atomic Force Microscopy (AFM) stiffness imaging by PeakForce Quantitative Nanomechanical Mapping (PF-QNM). The AFM imaging is supported by WAXS, SAXS, FTIR, and DSC measurements. The experimental results show that hard domains initially grown at the surface break apart at elevated temperatures (65 °C) and cannot be re-grown upon cooling. They require new microtoming to repeat the growth scenario. The detailed step-by-step submicron scale observations of the surfaces serve to show importance of the influence that microtoming and the time after its completion have on surface morphology, and that these shall be considered when studying polymer materials microscopically.