Maximizing Contact of Supersoft Bottlebrush Networks with Rough Surfaces To Promote Particulate Removal

Abstract

Efficient removal of particulates from a rough surface with a soft material through a “press and peel” method (i.e., an adhesion and release approach) depends on good conformal contact at the interface; a material should be sufficiently soft to maximize contact with a particle while also conforming to rough surface features to clean the entire substrate surface. Here, we investigate the use of bottlebrush networksextremely soft elastomers composed of macromolecules with polymeric side chainsas materials for cleaning model substrates of varying roughness. Formed through free-radical polymerization of mono- and dimethacrylate functionalized polysiloxanes, these solvent-free supersoft elastomers exhibit moduli comparable to those of solvated gels, allowing for a lower moduli regime of elastomers to be used in contact experiments than previously possible. By varying the macromonomer to cross-linker ratio, we study the effect of modulus on conformal contact and cleaning for materials that are as soft as gels while minimizing/negating physical and/or chemical concerns that using a traditional material may involve (e.g., changes in component concentrations, solvent evaporation, and syneresis). We study cleaning efficacy by quantifying the conformal contact between soft materials and rough substrates via a contact adhesion-based measurement. These results give insight into the correlation between shear modulus and conformal contact with surfaces of varying feature height. Not only does a decrease in shear modulus leads to improved conformal contact with rough surfaces, but also it facilitates adhesion to particulates situated on the rough surface, thus aiding removal. We highlight this property control with a case study illustrating the removal of an artificial soil mixture from a rough, acrylic surface via peeling rather than rubbing, which can cause damage to delicate surfaces.

Ultrasound-Stimulated PVA Microbubbles for Adhesive Removal from Cellulose-Based Materials: A Groundbreaking Low-Impact Methodology

“…Recently reported researches, indeed, agree with the idea that cleaning procedures, to be effective (also in terms of time and costs), should involve a close contact between the species used for the removal and the molecules to be removed. 15 , 23 , 44 …”

“…This hypothesis is in line with the new cleaning strategies aimed at using elastomeric microparticles to maximize contact at the interface with rough surfaces subjected to cleaning. 15 …”

“…Furthermore, gels can remove dust and solid contaminants via interfacial adhesion. 14 , 15 Their use has allowed the restoration of very fragile paper samples and the removal of specific materials like natural adhesives or greasy compounds. 11 , 16 − 19 Despite the great development of cleaning hydrogels, there are still several drawbacks.…”

“…The idea comes from the finding that successful cleaning needs an intimate contact of the material employed with both the substrate and compounds to be removed, as observed by comparing the times needed for a complete cleaning process with gellan hydrogel (1 h) or with the corresponding gellan microgels (few minutes). 10 , 14 , 15 , 23 It has been demonstrated that poly(vinyl alcohol) (PVA)-based hydrogels are good materials for cleaning both ancient and modern paper samples. 12 , 13 In addition, PVA-shelled microbubbles are very stable and acoustically active, thus representing a versatile tool to enhance the cleaning action with US.…”

An in-depth look at how physical properties of cleaning materials affect the removal of soot from rough papers

“…The cleaning methods explored include traditional (a dry swab; a cosmetic sponge; a soot sponge; a Wishab dry cleaning sponge; eraser crumbs; Absorene Paper, Book, and Paper Wallpaper cleaner; and Magic Rub #1954, art gum, and kneaded erasers) and one recently-proposed technology (a solvent-free Sylgard 184 elastomer that can remove particulates with a gentle 'press and peel' action 2,3 ). The visual changes to the paper substrates with cleaning are documented with two macroscopic techniques: photodocumentation of the paper substrates after cleaning (Figure 1) qualitatively illustrated the overall cleaning results and colorimetry measurements quantitatively served to determine cleaning efficacy.…”