The Relationship between Charge Density and Polyelectrolyte Brush Profile Using Simultaneous Neutron Reflectivity and In Situ Attenuated Total Internal Reflection FTIR

Topham, Paul D.; Glidle, Andrew; Toolan, Daniel T. W.; Weir, Michael P.; Skoda, Maximillian W. A.; Barker, Robert; Howse, Jonathan R.

doi:10.1021/la4005592

Cited by 26 publications

(29 citation statements)

References 43 publications

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“…The hysteresis between the swelling and collapse processes is most pronounced in the case of the poly(DEA) brush as previously reported. 13,25 This hysteric behaviour is further explored later when the kinetics of the brush swelling and collapse transitions is considered. It is also evident from Fig.…”

Section: Resultsmentioning

confidence: 99%

“…[14][15][16] These brushes have been shown to exhibit pH controllable interfacial lubrication, 5 wettability 17,18 and molecular transport, 19 as well as being used in combination with other polymers for the development of antimicrobial and infectionresistant surfaces. 20,21 The less studied and more hydrophobic poly(2-diethylamino)ethyl methacrylate (poly(DEA)) 13,[22][23][24][25][26] and poly(2-diisopropylamino)ethyl methacrylate (poly(DPA)) 4,22,27 analogues of poly(DMA) also display pH sensitive behaviour. Owing to their increased hydrophobicity, untethered poly(DEA) and poly(DPA) homopolymers have been shown to exhibit pH dependent solubility, being insoluble at neutral and basic pH at room temperature.…”

Section: Introductionmentioning

confidence: 99%

“…28,29 Significantly for brushes, the apparent pK a transition is broader still and may be shifted, since the protonation equilibrium of the tertiary amine groups (for polybases) is strongly influenced by the inherent confinement of the polymer chains. 13,32 While the equilibrium pH-response of individual polybasic brushes has received considered attention, 3,5,[13][14][15]22,25 herein we present a comprehensive comparative study of the dynamic behaviour of three polybasic tertiary amine methacrylates. Our previous studies have focussed on poly(DEA) brushes grown from both particulate and planar substrates where we have demonstrated highly reversible equilibrium behaviour (charge state, brush thickness and viscoelastic nature) within the pH range of 4 and 9.…”

Section: Introductionmentioning

confidence: 99%

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Hydrophobic effects within the dynamic pH-response of polybasic tertiary amine methacrylate brushes

Willott

Humphreys

Murdoch

et al. 2015

Phys. Chem. Chem. Phys.

118

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The solvation and swelling behaviour of three dialkylaminoethyl methacrylate polymer brushes, of varying hydrophobicity, have been investigated using a combination of in situ ellipsometry and a quartz crystal microbalance with dissipation (QCM-D). At low pH the tertiary amine groups of the three polymers are protonated and all three brushes are significantly solvated and swell by adopting an extended conformation. As the pH is increased the weak polybasic brushes become increasingly deprotonated and collapse via solvent expulsion. By employing high temporal resolution measurements we have found that monomer hydrophobicity has a direct influence on the dynamics of this pH-response. The most hydrophobic poly(2-diisopropylamino)ethyl methacrylate (poly(DPA)) brush exhibits the fastest maximum swelling rate. This maximum swelling rate is reduced with decreasing monomer hydrophobicity for the 2-diethylamino, and even further for the 2-dimethylamino analogues. For all three brushes, the corresponding collapse transition is slower and compounded by an induction time that decreases with monomer hydrophobicity. Here also, the maximum collapse rate is greatest for the most hydrophobic polymer. This domination of the pH-response kinetics by monomer hydrophobicity is attributed to attractive hydrophobic forces between polymer segments overcoming the repulsive electrostatic forces between the tertiary amine residues.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hydrophobic effects within the dynamic pH-response of polybasic tertiary amine methacrylate brushes

Willott

Humphreys

Murdoch

et al. 2015

Phys. Chem. Chem. Phys.

118

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“…r is the density of the PCL or PDEAEMA, which are assumed to be the values of bulk PCL (1.146 g cm À3 ) and bulk PDEAEMA (1.035 g cm À3 ). 52,53 (F À F min )/(F max À F) was plotted versus polymer concentration as shown in Fig. S3 † and K v (1.5 Â 10 5 -1.9 Â 10 5 ) of pyrene was obtained from the slope of the graph summarized in Table 1.…”

Section: Cmc Values Of (Pcl) 3 -(Pdeaema-b-ppegma)mentioning

confidence: 99%

Amphiphilic miktoarm star copolymer (PCL)3-(PDEAEMA-b-PPEGMA)3 as pH-sensitive micelles in the delivery of anticancer drug

et al. 2014

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Well-defined A 3 (BC) 3 type amphiphilic miktoarm star polymers poly(3-caprolactone) 3 -[poly (2-(diethylamino)ethyl methacrylate)-b-poly(poly(ethylene glycol) methyl ether methacrylate)] 3 [(PCL) 3 -(PDEAEMA-b-PPEGMA) 3 ] and their pH-sensitive self-assembled polymeric micelles were developed as anticancer vehicles for improved cancer therapy. These miktoarm star polymers were synthesized by a combination of ring opening polymerization (ROP) and continuous activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) and characterized by GPC and 1 H NMR measurement. The CMC values of the miktoarm star polymers in aqueous solution were extremely low (0.0029-0.0035 mg mL À1 ), suggesting that the micelles are relatively stable in solution. The selfassembled blank and doxorubicin (DOX)-loaded micelles were spherical in morphology with average sizes of 110-240 nm depending on the architecture of the copolymers, which were determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). When decreasing pH from 7.4 to 5.0, the micelles underwent globule-uneven-extended conformational transitions, and in vitro drug release rates were significantly accelerated, owing to the swelling of micelles at lower pH conditions caused by the protonation of tertiary amine groups of DEAEMA. Moreover, the drug release profiles at different pH values were well fitted by a semi-empirical equation. The in vitro cytotoxicity of DOX-loaded micelles against HepG2 cells suggested that DOX-loaded (PCL) 3 -(PDEAEMA-b-PPEGMA) 3 micelles exhibited similar anti-tumor activities to free DOX, with at least 80% decrease in cell viability after 48 h incubation. Intracellular uptake demonstrated that DOX was delivered into the cells effectively after the cells were incubated with DOX-loaded micelles. The results demonstrated that the pHresponsive (PCL) 3 -(PDEAEMA-b-PPEGMA) 3 micelles could be used as latent vehicles for delivering hydrophobic anticancer drugs with controlled and sustained release behavior.

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“…A slight shift to lower wavenumbers (0.4 cm −1 ) of the carbonyl band is observed for BNNT‐PMMA, in comparison to PMMA. The position of the carbonyl stretching band is sensitive to interactions and is observed to shift by several wavenumbers to lower values in the presence of electron‐deficient compounds 74,75 . In addition, both measured T g values for PMMA (108 °C) and BNNT‐PMMA (111 °C) are within the error margins (±3 °C) of the method.…”

Section: Resultsmentioning

confidence: 59%

Probing interfacial interactions and dynamics of polymers enclosed in boron nitride nanotubes

Niskanen

Golberg

Winnik

et al. 2021

Journal of Polymer Science

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Understanding interfacial interactions in polymer systems is crucial for their applicability for instance in adhesives and coatings. Enclosing polymers in a cylindrical volume provides a system for studying interactions dictated by a continuous interfacial layer and a bulk‐like volume in the middle of the cylinders. Here, we describe a simple method for enclosing polymers into boron nitride nanotubes (BNNTs) and establishing the effect of the interfacial interactions on the glass transition temperature (Tg) of the polymers by infrared spectroscopy. The volume of the inner channel is large in comparison to the volume of the loaded polymer coils, allowing the polymer to expand along the inner channel, resulting in the effect of interfacial interactions on polymer dynamics dominating over confinement effects. As examples, we loaded poly(4‐vinyl pyridine), poly(methyl methacrylate), poly(vinyl pyrrolidone), and poly(disperse red 1 acrylate) in BNNTs. The strongest interaction between the studied polymer and BNNTs was observed for poly(4‐vinyl pyridine), which also caused a significant increase of Tg. In addition to characterizing the effect of interfacial interactions on the thermal transitions of the polymers, this method, which is generalizable to most soluble polymer materials, can be used for studying photoinduced transitions in photoactive polymers thanks to the transparency of the BNNTs at visible wavelengths.

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The Relationship between Charge Density and Polyelectrolyte Brush Profile Using Simultaneous Neutron Reflectivity and In Situ Attenuated Total Internal Reflection FTIR

Cited by 26 publications

References 43 publications

Hydrophobic effects within the dynamic pH-response of polybasic tertiary amine methacrylate brushes

Hydrophobic effects within the dynamic pH-response of polybasic tertiary amine methacrylate brushes

Amphiphilic miktoarm star copolymer (PCL)3-(PDEAEMA-b-PPEGMA)3 as pH-sensitive micelles in the delivery of anticancer drug

Probing interfacial interactions and dynamics of polymers enclosed in boron nitride nanotubes

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