Indentation modulus and hardness of polyaniline thin films by atomic force microscopy

Elastic modulus measurements at variable temperature: Validation of atomic force microscopy techniques

“…The collected curves can be used to obtain a forceindentation curves which are analogous to those obtained in standard DSI, the approaching and retracting phases in I-AFM corresponding to the loading and unloading ones in DSI [22,23]. By varying the range of ∆z, different penetration depths can be achieved from a few to several tens or even a few hundreds of nanometers, which represents a key capability in the study of polymeric thin films on stiff substrates [24,25]. The cantilever deflection is related to the tip-sample interaction force (F N ) by the Hooke's law F N = k c d, where k c is the cantilever spring constant.…”

“…Analogous effects, but less marked, are observed on PC sample, too (curves not shown). To quantitatively evaluate the indentation modulus of the samples, the geometry of the tip should be calibrated using a set of reference materials [22][23][24]37]. In this work, however, indentation modulus values M at different temperatures were compared after normalization by the corresponding value at room temperature M 0 , in order to avoid the timeconsuming calibration step.…”

Contact resonance atomic force microscopy for viscoelastic characterization of polymer-based nanocomposites at variable temperature

“…Due to its high spatial resolution, nanometer dimensions of the probed volume of materials, and nondestructive nature of measurements, AFM is currently a broadly used tool for the mechanical investigation of polymers community. AFM-based quasi-static nanoindentation is a well-established technique for the characterization of elastic properties of compliant materials [7,8], also when they are represented by layered ultrathin films on stiff substrates [9,10]. Also, it can be used to study viscoelasticity of soft materials through relaxation indentation tests [11].…”

Atomic Force Microscopy Techniques for Nanomechanical Characterization: A Polymeric Case Study

“…Among these techniques, AFM nanoindentation 1 is the simplest method used to evaluate the local mechanical properties of both stiff and soft samples. [2][3][4][5] AFM nanoindentation consists in locally recording force-indentation (FI) curves. If the FI curves are collected at each point of the scanning area, then a stiffness map of the sample is obtained in the socalled force volume mode.…”

“…[14][15][16][17] In previous studies, by adopting the above-mentioned AFM techniques (i.e., AFM nanoindentation, CR-AFM, and TH-AFM), we deeply analyzed the mechanical properties of hybrid nanocomposite materials based on conductive polymers, i.e., polyaniline (PANI) and poly (3,4-ethylenedioxythiophene) (PED-OT) filled with nanodiamond (ND) particles. 5,[17][18][19][20][21][22] In particular, we have pointed out that ND is able to induce a high structural order of the polymerchains that organize themselves in the form of nanofibrils, nanoglobules, or nanoparticles depending on the experimental conditions of the synthesis. On such materials, we performed accurate material characterizations at the nanoscale.…”