Recoverable surface modification using dendritically fluorocarbon‐functionalized poly(methyl methacrylate)

Abstract

Dendritically fluorocarbon‐functionalized poly(methyl methacrylate) (PMMA) has been explored as a robust surface‐modifying additive in PMMA blends. These functionalized materials, denoted FxPMMAy, where x is the number of C8F17 fluorocarbon groups per dendron connected to a PMMA chain of y kg/mol, have been synthesized by living radical polymerization. These materials adsorb efficiently to the surfaces of their blends with unfunctionalized PMMA, resulting in increased hydrophobicity and lipophobicity. Contact‐angle goniometry has indicated a substantial reduction in the surface energy toward polytetrafluoroethylene‐like surface properties in the case of pure F4PMMA8.6 and substantial, but incomplete fluorocarbon surface coverage at a lower FxPMMAy concentration. The partial coverage has been confirmed by Rutherford backscattering and, together with the weak dependence of the surface modification on the FxPMMAy structure, indicates incomplete equilibrium of the surface adsorption. The modified surfaces are quite durable with respect to abrasion under water but are progressively eroded when the double‐wipe test is carried out with acetone. FxPMMAy, dispersed in the remaining film, acts as a reservoir of spare functional groups, from which the damaged surface may be replenished, leading to the recovery of the modified surface properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Modifying polyester surfaces with incompatible polymer additives

“…Our previous experiments indicate that when comparable length functionalised PMMA is compatible with the matrix, it is quite stable with respect to abrasion in water, but less so with acetone. 35 However, for maximum mechanical stability, brush-like layers need to be well-entangled with the subphase, 36 which is not possible for PS materials of this molecular weight, particularly with an incompatible matrix.…”

Surface Modification of Polyethylene with Multi-End-Functional Polyethylene Additives

“…Furthermore, the polymeric additives have less impact on the bulk properties of the polymer matrix than small molecule additives, and may act as a reservoir of spare functionality from which damaged surfaces may be regenerated. 11 Until now, we have focused on model amorphous systems, which, when compared to semi crystalline polymers, are much more amenable to characterization by techniques such as neutron reflectometry which require very smooth homogeneous surfaces. In fact, studies of end functional polymers in blends with crystalline materials are scarce, 12 despite their ubiquitous importance to many technological areas of application.…”

Synthesis and characterisation of end-functionalised poly(N-vinylpyrrolidone) additives by reversible addition–fragmentation transfer polymerisation

“…Moreover, the low molecular weight polymer additive can easily be incorporated into the matrix polymer during a processing step; surface migration occurring whilst the polymer is still in the melt, above the glass transition or in the presence of solvent. This has been shown to be the case for both spin coating of thin films [27][28][29][30][31][32][33][34][35] and electrospinning of fibres. 44 The polymer additive approach offers one further advantage over the methods mentioned above in that functionalised additives, depending on the nature of the functional group, have the ability to functionalise buried interfaces as well as air-polymer surfaces.…”

“…We have previously described the synthesis of a number of similar polymer additives by atom transfer radical polymerisation [29][30][31][32] and ring opening polymerisation 33 in which the multifunctional end group was introduced through the use of a functionalised initiator. We have also previously described a synthesis of analogous additives by living anionic polymerisation and subsequent endcapping, necessitated by anionic polymerisation's sensitivity to functionality and impurities.…”

“…The functionalized additives behave largely like macromolecular surfactants 27,28 in so much that the functional groups are tethered to the chain-end of a polymer which is preferably identical to (or a least compatible with) the bulk polymer whose surface is to be modified. Moreover, it is a very versatile concept and a wide range of polymer additives have been prepared by a variety of polymerization mechanisms including polystyrene and poly(methyl methacrylate) by atom transfer radical polymerization [29][30][31][32] polylactide by ring opening polymerization 33 , polystyrene, polyisoprene and polybutadiene by anionic polymerization 34 and polyethylene 35 via the hydrogenation of high 1,4-polybutadiene prepared by anionic polymerization. Whereas the addition of functional additives is by no means the only way to modify surface properties, the described concept has several advantages over other methods of surface modification such as plasma treatment, 14,[36][37][38] wet chemical modification [39][40][41] and the application of polymeric surface coatings.…”