Effect of Oligomer Segregation on the Aggregation State and Strength at the Polystyrene/Substrate Interface

Abstract

The interfacial strength of polystyrene (PS) with and without PS oligomers in contact with a glass substrate was examined to determine the relationship between the interfacial aggregation state and adhesion. The shear bond strength and adsorbed layer thickness of neat PS exhibited a similar dependence on the thermal annealing time: they increased to constant values within almost the same time. This implies that the adhesion of the polymer is closely related to the formation of an adsorbed layer at the adhesion interface. Nevertheless, in the case of PS with a small amount of oligomer, the shear bond strength decreased, while the adsorbed layer thickness was almost the same as that of neat PS. Based on the results of interfacial analyses, we propose that the interfacial segregation of the oligomer reduced the entanglement between the interfacial free chains in the adsorbed layer and the bulk chains.

Effects of Polarity of Polymers on Conformation and Lubricating Film Formation of Adsorbed Films

“…Recent studies on interpolymer adhesion of adsorbed films have shown that free bulk polymers can penetrate loosely adsorbed chains. The loosely adsorbed chains act as “connecters” that bridge bulk chains and the substrate, leading to strong adhesion. − This is in contrast to flattened chains which show “autophobic” behavior with bulk free chains, and no adhesion is found between chemically identical polymer chains . Therefore, the loosely adsorbed chains of the PMA-C8 (EH) film could have trapped the free polymer chains that flowed into the gap from outside the contact area, which would have resulted in a larger gap during sliding.…”

Absolute local conformation of poly(methyl methacrylate) chains adsorbed on a quartz surface

“…The dynamics of chains in the interfacial layer are markedly different from those of the corresponding bulk chains [34][35][36][37][38][39][40][41][42][43][44] . These characteristics of chains in the interfacial layer are universal for rubbery and glassy polymers [45][46][47][48][49] , as mentioned above, and are closely related to the mechanical properties of the polymer nanocomposites [50][51][52][53][54][55] .…”

Enhanced Sum Frequency Generation for Monolayers on Au Relative to Silica: Local Field Factors and SPR Effect

“…As a second-order nonlinear optical technique, sum frequency generation (SFG) vibrational spectroscopy, with intrinsically molecular-level selectivity and sensitivity at surfaces and interfaces, has been developed into a powerful tool to specifically probe surfaces and interfaces where the inversion symmetry is broken under the electrical dipole approximation. − Meanwhile, surface-enhanced SFG has been utilized to detect molecules on metals or nanoparticle surfaces. − Nonetheless, analogous to nonlinear coherent vibrational spectroscopy, one of the biggest issues regarding SFG is the strong interference between nonresonant (NR) signals and molecular resonance signals in terms of the peak position, peak width, amplitude, and phase, − leading to the peak shift and distortion and even the creation of ghost peaks . This problem is frequently a barrier to the SFG spectral analysis, especially when interpreting the SFG spectra of surface-anchored molecules on metals where the NR signals drastically overwhelm the molecular resonant signals.…”