Journal: National Science Review

Article Title: The anomalous effect of electric field on friction for microscale structural superlubric graphite/Au contact

doi: 10.1093/nsr/nwae019

Figure Lengend Snippet: Experimental set-up and samples for current-carrying friction measurements. (a) Experiment set-up. (b) Two contact states of graphite and Au: the ‘edge contact’ (top part) and ‘in-plane contact’ (sub part). (c) The SEM image of the two types of contacts, corresponding to the states illustrated in (b). (d) The topography of the Au surface by AFM scanning. The inset showing the profile of the red line.

Article Snippet: The experiment was conducted using a home-built source meter-atomic force microscope (AFM) platform, as illustrated in Fig. . A visible AFM tip (VIT_P AFM probe, NT-MDT, Russia) was in close contact with the Pt cap to restrict the motion of the graphite flake.

Techniques:

Journal: Nanomaterials

Article Title: Nano/Microscale Thermal Field Distribution: Conducting Thermal Decomposition of Pyrolytic-Type Polymer by Heated AFM Probes

doi: 10.3390/nano10030483

Figure Lengend Snippet: Schematic of an atomic force microscope (AFM) heated probe tip hovering above the polyphthalaldehyde (PPA) film on a silicon substrate to fabricate the pyramid decomposition structure (air gap). ( a ) The integrated heater area, lying above the tip free end, is electrified through the cantilever to heat the tip by controlling the VITA TM heating module. The resulting heat fluxes are represented by the orange arrows for the different modes of heat lost: through the cantilever legs ( q leg ) and tip ( q t ) by conduction, from the tip to environment ( q evr ) by conduction, from the tip to PPA film ( q gap ) by conduction, and the radiation ( q rad ). The decomposition of PPA film, which causes a pyramid air gap structure to form on its surface, is induced by q gap . ( b ) The cross-section plot of the sample underneath the heated cantilever (being mounted at an angle of ~12°) showing the dimension of the air gap structure changing with the increasing tip temperature and heating time. The horizontal and vertical sizes of the air gap structure are indicated by the two double-headed arrows, which are located on and perpendicular to the PPA surface and marked by L dec and h dec , respectively.

Article Snippet: The array of pyramid decomposition structures (air gaps) on the PPA film was fabricated by a heatable AFM probe through the following three steps in an atmospheric air environment: (i) The heated tip with the room temperature was positioned in contact with the PPA film surface with an initial contact force ~20 nN; (ii) the tip temperature was instantaneously raised to the preset temperature (ranging from 190–220 °C) by applying a fixed voltage to the integrated heater via the cantilever while the tip was controlled by the scanner to stay at the initial location for a specified heating duration (ranging from 0.3 to 120 s); and (iii) after stopping heating, the heated tip was cooled for 10 s to ensure that its temperature was low enough to avoid inducing decomposition [ ] and then moved to the next preselected position by controlling the scanner.

Techniques: Microscopy

Journal: Nanomaterials

Article Title: Nano/Microscale Thermal Field Distribution: Conducting Thermal Decomposition of Pyrolytic-Type Polymer by Heated AFM Probes

doi: 10.3390/nano10030483

Figure Lengend Snippet: ( a ) AFM topographic image of the pyramid air gap structures on the film surface formed by using a heated tip to induce localized PPA decomposition. The corresponding tip temperatures (190–220 °C) and heating duration (0.3–30 s) for each experimental air gap are shown in the left and bottom side of the image, respectively. ( b ) The cross-section plot of the position marked in (a) by a blue line. The method for measuring the feature sizes ( L dec and h dec ) of the air gap structures is shown in the right-side structure section. ( c ) AFM imaging plot of the pyramid air gap structures formed under the condition of the heating duration of 60–120 s and the tip temperature of 190–220 °C. For the tip temperature of 205 °C, the values of the two feature sizes of the structures are given, close below the corresponding structure. ( d ) The cross-section plot of the position marked in (c) by a red line.

Article Snippet: The array of pyramid decomposition structures (air gaps) on the PPA film was fabricated by a heatable AFM probe through the following three steps in an atmospheric air environment: (i) The heated tip with the room temperature was positioned in contact with the PPA film surface with an initial contact force ~20 nN; (ii) the tip temperature was instantaneously raised to the preset temperature (ranging from 190–220 °C) by applying a fixed voltage to the integrated heater via the cantilever while the tip was controlled by the scanner to stay at the initial location for a specified heating duration (ranging from 0.3 to 120 s); and (iii) after stopping heating, the heated tip was cooled for 10 s to ensure that its temperature was low enough to avoid inducing decomposition [ ] and then moved to the next preselected position by controlling the scanner.

Techniques: Imaging

Journal: Nanomaterials

Article Title: Nano/Microscale Thermal Field Distribution: Conducting Thermal Decomposition of Pyrolytic-Type Polymer by Heated AFM Probes

doi: 10.3390/nano10030483

Figure Lengend Snippet: AFM topographic images of the pyramid air gap structures and the cross-section plot of the marked location. The heating times in the topographic images were 0.3 s ( a ), 15 s ( b ), 30 s ( c ), and 120 s ( d ), the tip temperature was kept at 205 °C. The height cross-section plot of the location marked by corresponding color lines are shown in ( g ), ( h ), ( i ) and ( j ), respectively. (a) The white arrow points to the initial tip-sample contact point. (b) The white dashed lines schematically show the cantilever orientation (not to scale). The area enclosed by red dashes is the deviation area of the surface contour away from a symmetric rhombus. ( e ) The cross-section plot along the blue dashed line in (b), showing the accurately geometric shape of the heated tip and the relative position of the cantilever as well as the tip and the air gap structure on the PPA surface. Scanning electron microscope (SEM) image provided by (Reproduced with permission from . Copyright, Springer, 2007). ( f ) Magnified image of the blue dashed frame in (e). The solid red line approximately parallel to the z axis passing through the tip peak shows the projection of the front tip edge at the cross section. The red circular area represents an arbitrary heating area on the heated tip surface few micrometers close to the tip apex. The scale bar is given in the lower right corner.

Article Snippet: The array of pyramid decomposition structures (air gaps) on the PPA film was fabricated by a heatable AFM probe through the following three steps in an atmospheric air environment: (i) The heated tip with the room temperature was positioned in contact with the PPA film surface with an initial contact force ~20 nN; (ii) the tip temperature was instantaneously raised to the preset temperature (ranging from 190–220 °C) by applying a fixed voltage to the integrated heater via the cantilever while the tip was controlled by the scanner to stay at the initial location for a specified heating duration (ranging from 0.3 to 120 s); and (iii) after stopping heating, the heated tip was cooled for 10 s to ensure that its temperature was low enough to avoid inducing decomposition [ ] and then moved to the next preselected position by controlling the scanner.

Techniques: Microscopy

Journal: Nanomaterials

Article Title: Nano/Microscale Thermal Field Distribution: Conducting Thermal Decomposition of Pyrolytic-Type Polymer by Heated AFM Probes

doi: 10.3390/nano10030483

Figure Lengend Snippet: Patterning pyramid structure on the PPA film. ( a ) Three-dimensional image of pyramid structures (in a). ( b ) AFM topographic image of patterning structures. The heating time was 30 s, and the tip temperature was 245 °C. ( c ) The height cross-section plot of the position marked by the blue/red/green line in (b). The size and shape of every pyramid decomposition structure were all the same. The feature sizes of the structure, max L dec and max h dec were 1505 ± 18.4 nm and 263.3 ± 1.9 nm, respectively.

Article Snippet: The array of pyramid decomposition structures (air gaps) on the PPA film was fabricated by a heatable AFM probe through the following three steps in an atmospheric air environment: (i) The heated tip with the room temperature was positioned in contact with the PPA film surface with an initial contact force ~20 nN; (ii) the tip temperature was instantaneously raised to the preset temperature (ranging from 190–220 °C) by applying a fixed voltage to the integrated heater via the cantilever while the tip was controlled by the scanner to stay at the initial location for a specified heating duration (ranging from 0.3 to 120 s); and (iii) after stopping heating, the heated tip was cooled for 10 s to ensure that its temperature was low enough to avoid inducing decomposition [ ] and then moved to the next preselected position by controlling the scanner.

Techniques:

Journal: Frontiers in Neuroscience

Article Title: Bidirectional Modulation of Neuronal Cells Electrical and Mechanical Properties Through Pristine and Functionalized Graphene Substrates

doi: 10.3389/fnins.2021.811348

Figure Lengend Snippet: Fabrication and characterization of pSLG and fSLG. (A) Scheme of the graphene transfer process from copper to glass exploiting an electrochemical delamination procedure: (i) CVD-grown single-layer graphene on copper; (ii) deposition of a supportive PMMA film; (iii) electrochemical delamination; (iv) free-standing graphene/PMMA layers; (v) transfer on glass; (vi) dissolution of the sacrificial PMMA layer. (B) Average of 20 randomly-acquired Raman spectra of a graphene sample before the chemical functionalization (pSLG, in black) and after (fSLG, in red) exhibiting the typical bands of CVD graphene in both conditions (ΔI D /I G of about 0.29). It is worth noting that peaks’ shape was impacted by the sporadic presence of double layer nucleation sites. (C) Schematic of the diazonium coupling onto pSLG by using 4-(carboxymethyl)benzene diazonium tetrafluoroborate to obtain fSLG. (D) Box plot of the I D /I G ratio for pSLG and fSLG. The plot showed a significant change after functionalization reaction, which confirms the covalent modification of graphene. (E) AFM topographic images of glass (left), pSLG (middle), and fSLG (right) surfaces before cell plating. Below, the representative topographic profiles relative to the highlighted lines in the images are shown.

Article Snippet: Both topographic and phase signal images were acquired using silicon AFM tips (Etalon ® HA-NC rectangular cantilevers, spring constant 12 nN/nm, resonant frequency 235 kHz, probe tip radius 10 nm, NT-MDT Co., RU).

Techniques: Dissolution, Modification