Xyloglucan-Functional Latex Particles via RAFT-Mediated
Emulsion Polymerization for the Biomimetic Modification of Cellulose
Fiona
L. Hatton
Marcus Ruda
Muriel Lansalot
Franck D’Agosto
Eva Malmström
Anna Carlmark
10.1021/acs.biomac.6b00036.s001
https://acs.figshare.com/articles/journal_contribution/Xyloglucan_Functional_Latex_Particles_via_RAFT_Mediated_Emulsion_Polymerization_for_the_Biomimetic_Modification_of_Cellulose/3084469
Herein,
we report a novel class of latex particles composed of
a hemicellulose, xyloglucan (XG), and poly(methyl methacrylate) (PMMA),
specially designed to enable a biomimetic modification of cellulose.
The formation of the latex particles was achieved utilizing reversible
addition–fragmentation chain transfer (RAFT) mediated surfactant-free
emulsion polymerization employing XG as a hydrophilic macromolecular
RAFT agent (macroRAFT). In an initial step, XG was functionalized
at the reducing chain end to bear a dithioester. This XG macroRAFT
was subsequently utilized in water and chain extended with methyl
methacrylate (MMA) as hydrophobic monomer, inspired by a polymerization-induced
self-assembly (PISA) process. This yielded latex nanoparticles with
a hydrophobic PMMA core stabilized by the hydrophilic XG chains at
the corona. The molar mass of PMMA targeted was varied, resulting
in a series of stable latex particles with hydrophobic PMMA content
between 22 and 68 wt % of the total solids content (5–10%).
The XG-PMMA nanoparticles were subsequently adsorbed to a neutral
cellulose substrate (filter paper), and the modified surfaces were
analyzed by FT-IR and SEM analyses. The adsorption of the latex particles
was also investigated by quartz crystal microbalance with dissipation
monitoring (QCM-D), where the nanoparticles were adsorbed to negatively
charged model cellulose surfaces. The surfaces were analyzed by atomic
force microscopy (AFM) and contact angle (CA) measurements. QCM-D
experiments showed that more mass was adsorbed to the surfaces with
increasing molar mass of the PMMA present. AFM of the surfaces after
adsorption showed discrete particles, which were no longer present
after annealing (160 °C, 1 h) and the roughness (<i>R</i><sub>q</sub>) of the surfaces had also decreased by at least half.
Interestingly, after annealing, the surfaces did not all become more
hydrophobic, as monitored by CA measurements, indicating that the
surface roughness was an important factor to consider when evaluating
the surface properties following particle adsorption. This novel class
of latex nanoparticles provides an excellent platform for cellulose
modification via physical adsorption. The utilization of XG as the
anchoring molecule to cellulose provides a versatile methodology,
as it does not rely on electrostatic interactions for the physical
adsorption, enabling a wide range of cellulose substrates to be modified,
including neutral sources such as cotton and bacterial nanocellulose,
leading to new and advanced materials.
2016-02-25 00:00:00
molar mass
PMMA
AFM
PISA
latex particles
model cellulose surfaces
quartz crystal microbalance
SEM
CA
XG
MMA
latex nanoparticles
adsorption
novel class