Bundle structure formation on a polymer film at various temperatures and scanning velocities

Abstract

The structures formed by atomic force microscopic tip scanning on a 133 nm thick poly(tert-butyl acrylate) (PtBuA) film were examined at temperatures ranging from room temperature to 58• C with various scanning velocities from 1 to 20 µm s −1 . It was observed that bumps were created at low temperatures and high scanning velocities. As the temperature was increased and the scanning velocity was decreased, bundles were produced through aggregation of the bumps. The width of the bundles was about 100 nm. As the temperature was further increased to higher than the glassy-rubbery phase transition temperature, T g ∼ 50• C, of the PtBuA polymer, no bundle structures were formed at low scanning velocities. Our results clearly indicate that the formation of bumps and bundles occurs from the interplay of polymer peeling and relaxation. With polymer peeling taking place on soft polymer surfaces, slower relaxation favours the accumulation of polymer coil displacement and the formation of the bump and bundle structures, while fast relaxation results in the recovery of the polymer perturbation and no formation of surface structures.

Depth profiling of polymer films with grazing-incidence small-angle X-ray scattering

“…Crosssectional scanning electron microscopy (SEM) images of the film structure indicated the presence of a 'bumpy' structure ( Fig. 5) similar to that reported by Wang et al (2002) for films of pure PtBuA as a result of AFM measurements. The cause of the observed film structure in this case has not yet been determined.…”

Surface rippling induced by periodic instabilities on a polymer surface

“…For an overview on these and related processes, the reader is referred to a recent review by Li et al [4]. On the nanoscale, the formation of wavy ripple patterns on compliant surfaces has been frequently reported in atomic force microscopy (AFM) measurements in contact mode [5][6][7][8][9][10][11][12][13][14][15][16][17]. In this case, the ripple periodicity λ is found to be slightly larger than the size of the tip apex, and strongly influenced by external conditions such as normal force, scan velocity and temperature [13,[17][18][19], while none of the two aforementioned macroscopic processes has been observed.…”

Nanoscale rippling on polymer surfaces induced by AFM manipulation

“…Regarding some crystalline materials, D’Acunto [ 10 – 11 ] and Filippov et al [ 12 ] have successfully reproduced the experimental data via computational methods. Nevertheless, it is for polymeric films that the ripple formation has been studied most extensively [ 13 – 19 ]. Ripple structures on polymers can be produced either by performing a single scan or many scans on the same area of the sample.…”