Voltage-assisted asperity formation in styrene butadiene at room temperature: Cross-linking at the nanoscale

Abstract

Nanoscale surface modification is reported for styrene butadiene rubber using an electrically biased conducting atomic force microscope tip. Under appropriate bias conditions, the local electric field magnitude is of the order of 10 8 -10 9 V m −1 , which is sufficiently large to initiate cross-linking in the rubber. Peaklike surface features, surrounded by a circular trough and a raised ring, are created by careful and controlled retraction of the biased tip. The features' aspect ratios can be controlled by modifying the tip retraction protocol, tip geometry, and bias voltage. Typical feature dimensions reported here vary from approximately ͑0.5-10͒-nm high and up to several hundreds of nanometer in diameter. Although the temperature of the rubber is above the glass transition and the rubber is in a viscous state, the features are stable over a period of several days once created-which is believed to be due to cross-linking of the rubber during feature formation. Modeling of the electric field distribution in the vicinity of the tip is presented, which strongly supports the assertion that the resulting nonuniform electric field induces nanostructure formation and initiates cross-linking. A mechanism is proposed whereby source material is redistributed in the proximity of the tip/surface region to form the observed features.

Atomic force microscopy electrostatic nanolithography (AFMEN): a versatile tool for nano-patterning in thin films and beyond

“…AFMEN in styrene butadiene rubber: We combine AFMEN with the tip manipulation to pattern nanostructures in the SBR. A prime goal was to elucidate the macromolecule behavior in extreme electric field 10 9 Vm -1 using modified AFMEN protocol [6]. The results of nanopatterning are presented in Fig.…”

“…Essentially AFMEN causes the polymer to deform and flow to the shape of the applied electric field. During past decade, the AFMEN and its modifications have proven to be effective when applied in graphene fluoride (GF) [4], silicon pretreated with solvents [5], and styrene butadiene rubber (SBR) [6].…”

Electric charging and nanostructure formation in polymeric films using combined amplitude-modulated atomic force microscopy-assisted electrostatic nanolithography and electric force microscopy

“…Atomic Force Microscopy Electrostatic Nanolithography (AFMEN) is a technique that can be used for patterning and functionalization at the nanoscale (20 -100 nm). It is a technique that has shown to be applicable to a wide variety of materials including PMMA, PS, CdS, Si, and SBR 19,45,46 . We will demonstrate that the process is also The advantage to this protocol is repeatability and ability to produce variable height nanostructures with a high degree of precision.…”

“…This technique combines the two protocols to produce a method that allows even more control over feature formation. It has been utilized to induce cross linking at the nanoscale in SBR 46 and it shall be demonstrated in this research that it is an effective way to deposit charge at the nanoscale 47…”