Polymer brushes: Applications in biomaterials and nanotechnology

Ayres, Neil

doi:10.1039/b9py00246d

Cited by 253 publications

(205 citation statements)

References 155 publications

(155 reference statements)

Supporting

Mentioning

205

Contrasting

Order By: Relevance

“…In terms of useful physical, chemical and biomedical applications, brushes can be used to stabilise colloids, lubricate surfaces, deliver drugs by biodegradable micelles, in DNA microarrays for diagnostic analysis of mutations and to reduce friction in artificial joints, to name but a few. 13 Here we present a simple, planar brush of self-avoiding bead-and-spring polymer chains without additional electrostatic interactions or hydrodynamics, which makes the analysis tractable and comparable with well-established theories -but we also examine the case of chains with a long persistence length as a crude attempt to account for polyelectrolyte stiffening. The simple picture of polymer brushes may serve as the basis for models in diverse interfacial systems in biophysics and polymer science, such as polymeric surfactants, stabilised suspensions of colloid particles, and many structures formed by block copolymers.…”

Section: Introductionmentioning

confidence: 99%

Arrested Spinodal Decomposition in Polymer Brush Collapsing in Poor Solvent

2015

View full text Add to dashboard Cite

We study the Brownian dynamics of flexible and semiflexible polymer chains densely grafted on a flat substrate, upon rapid quenching of the system when the quality of solvent becomes poor and chains attempt collapse into a globular state. The collapse process of such a polymer brush differs from individual chains, both in its kinetics and its structural morphology. We find that the resulting collapsed brush does not form a homogeneous dense layer, in spite of all chain monomers equally attracting each other via a model Lennard-Jones potential. Instead, a very distinct inhomogeneous density distribution in the plane forms, with a characteristic length scale dependent on the quenching depth (or equivalently, the strength of monomer attraction) and the geometric parameters of the brush. This structure is identical to the spinodaldecomposition structure, however, due to the grafting constraint we find no subsequent coarsening: the established random bundling with characteristic periodicity remains as the apparently equilibrium structure. We compare this finding with a recent field-theoretical model of bundling in a semiflexible polymer brush.

show abstract

Section: Introductionmentioning

confidence: 99%

Arrested Spinodal Decomposition in Polymer Brush Collapsing in Poor Solvent

2015

View full text Add to dashboard Cite

show abstract

“…Very often they are responsive to external and/or environmental stimuli, such as electric fields [6,7], temperature [5,8], pH [9,10], and salt [11,12]. In recent years, polymer brushes have been shown to be a useful class of materials for many medical and biological applications [13,14]. For example, custom synthetic polymers have great potential in drug delivery and molecular recognition [15], and tethering polymer chains onto surfaces can effectively reduce friction [16,17], and control adhesion [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Al-Baradi

Tomlinson

Zhang³

et al. 2015

Polymer

View full text Add to dashboard Cite

The molar mass and dispersity of a polycation, poly[2-(dimethyl amino)ethyl methacrylate)] (PDMAEMA) grafted from a poly(methyl methacrylate) (PMMA) backbone, was measured by single-molecule force spectroscopy (SMFS) and shown to be consistent with results from gel permeation chromatography for the same comb polymer in aqueous solution. Comparison was then made between the comb polymer and PDMAEMA brushes that were grown from the substrate, as a function of the pH and ionic strength of the surrounding medium, and the limits of reliable characterization of the polymers are determined. A large discrepancy was observed between the responses of the comb and brush layer at low pH when the PDMAEMA molecules are extended from the supporting substrate. Here it is believed that the atomic force microscope (AFM) tip can penetrate the comb layer and selectively desorb side-chains of the comb. In the case of the well solvated PDMAEMA brushes at high pH, the tip preferentially selects larger chains, resulting in an over-estimate of the brush molar mass. The addition of salt also influenced the molar mass obtained by this technique. It is believed that salted brushes did not adhere well to the AFM tip, with subsequent desorption resulting in an underestimate of the molar mass. However, SMFS was shown to be capable of demonstrating the effect of salt on brush conformation, with greater swelling after the addition of a small amount of NaCl, but a significant decrease when 100 mM is added.

show abstract

“…The properties of polyelectrolyte brushes, including their structure [10][11][12] , mechanical and lubrication properties [13][14][15][16] , and their responses to changing pH and electrolyte conditions 10,11,[16][17][18][19][20][21][22][23] have thus been widely investigated (for reviews see e.g. [24][25][26][27] ).…”

Section: Introductionmentioning

confidence: 99%

Structure and Collapse of a Surface-Grown Strong Polyelectrolyte Brush on Sapphire

et al. 2012

View full text Add to dashboard Cite

We have used neutron reflectometry to investigate the behavior of a strong polyelectrolyte brush on a sapphire substrate, grown by atom transfer radical polymerization (ATRP) from a silane-anchored initiator layer. The initiator layer was deposited from vapor, following treatment of the substrate with an Ar/H 2 O plasma to improve surface reactivity. The deposition process was characterized using X-ray reflectometry, indicating the formation of a complete, cross-linked layer. The brush was grown from the monomer [2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC), which carries a strong positive charge. The neutron reflectivity profile of the swollen brush in pure water (D 2 O) showed that it adopted a two-region structure, consisting of a dense surface region ∼ 100 Å thick, in combination with a diffuse brush region extending to around 1000 Å from the surface. The existence of the diffuse brush region may be attributed to electrostatic repulsion from the positively-charged surface region, while the surface region itself most probably forms due to polyelectrolyte adsorption to the hydrophobic initiator layer. The importance of electrostatic interactions in maintaining the brush region is confirmed by measurements at high (1 M) added 1:1 electrolyte, which show a substantial transfer of polymer from the brush to the surface region, together with a strong reduction in brush height. On addition of 10 -4 M oppositely-charged surfactant (sodium dodecyl sulfate SDS), the brush undergoes a dramatic collapse, forming a single dense layer about 200 Å in thickness, which may be attributed to the neutralization of the monomers by adsorbed dodecyl sulfate ions in combination with hydrophobic interactions between these dodecyl chains. Subsequent increases in surfactant concentration result in slow increases in brush height, which may be caused by stiffening of the polyelectrolyte chains due to further dodecyl sulfate adsorption.3

show abstract

Polymer brushes: Applications in biomaterials and nanotechnology

Cited by 253 publications

References 155 publications

Arrested Spinodal Decomposition in Polymer Brush Collapsing in Poor Solvent

Arrested Spinodal Decomposition in Polymer Brush Collapsing in Poor Solvent

Determination of the molar mass of surface-grafted weak polyelectrolyte brushes using force spectroscopy

Structure and Collapse of a Surface-Grown Strong Polyelectrolyte Brush on Sapphire

Contact Info

Product

Resources

About