Investigating the adsorption of anisotropic diblock copolymer worms onto planar silica and nanocellulose surfaces using a quartz crystal microbalance

Joakim Engström,Eva Malmström,Emma E Brotherton,Michael S Reid,Steven P Armes,Fiona L Hatton

doi:10.1039/d1py00644d

Joakim Engström, Eva Malmström + Show 4 more

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https://doi.org/10.1039/d1py00644d

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Abstract

We report physical adsorption of highly anisotropic copolymer worms with either anionic or cationic charge onto planar silica, cellulose nanocrystal or cellulose nanofibril surfaces using a quartz crystal microbalance with dissipation monitoring.

Highlights

Acidic conditions were chosen to avoid ionization of the carboxylic acid end-groups conferred by the CECPA reversible addition–fragmentation chain transfer (RAFT) agent, which is known to prevent the formation of diblock copolymer worms.[49]
The original linear anionic PGMA25-PGlyMA45 worms and crosslinked cationic PGMA25-P(GlyMA-EDA)[45] worms were evaluated for their adsorption onto planar silica and nanocellulose (CNC, cellulose nanofibril (CNF)) surfaces using quartz crystal microbalance (QCM)-D
The adsorption of copolymer worms onto an in situ generated CNF surface revealed relatively strong adsorption for both the anionic worms and the cationic worms, which cannot be explained in terms of electrostatic interactions

Summary

Introduction

Cellulose has become widely recognized as an important sustainable biorenewable material owing to its abundance and excellent mechanical properties.[1,2,3] The isolation of nanocelluloses, such as cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial nanocellulose (BNC) has enabled the development of cellulosic materials for value-added applications,[2,4,5,6] such as energy-related devices,[7] biomedical applications[8] and nanocomposites.[9,10] unmodified cellulosic nanomaterials are hydrophilic in nature, undergo aggregation on drying, and are poorly compatible with hydrophobic components and matrices. CNFs are attractive nanocellulosic materials for the construction of free-standing films owing to their high aspect ratio, with mean lengths of the order of microns and diameters of around 5–20 nm, depending on the original source and production method.[2,16] This anisotropy leads to interesting aqueous dispersion properties: physical gels can be obtained at relatively low concentration (

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