Density Effects on Collapse, Compression, and Adhesion of Thermoresponsive Polymer Brushes

Malham, Ibrahim Bou; Bureau, Lionel

doi:10.1021/la9035387

Cited by 129 publications

(212 citation statements)

References 54 publications

Supporting

Mentioning

188

Contrasting

Order By: Relevance

“…Theoretical predictions for h swell [44,45] allow us to obtain the following expression for the swelling ratio of a brush, as detailed in previous work [24]:…”

Section: B Brush Swelling At Room Temperaturementioning

confidence: 99%

“…(i) Surface Plasmon Resonance [16] (SPR) (ii) Quartz-Crystal Microbalance [17][18][19][20][21][22] (QCM) (iii) force measurement techniques such as the Surface Forces Apparatus [23,24] (SFA) or Atomic Force Microscopy [21,22,[25][26][27] (AFM) (iv) Neutron Reflectivity [28][29][30] (NR) (v) in-situ Spectral Ellipsometry [31,32] (SE). While SPR and QCM studies give access to the qualitative evolution of the brush refractive index or effective mass with temperature, force measurements allow the inference of the temperature-dependent brush swelling from the range of steric repulsive forces measured, and only NR and SE (or, equivalently, multi-angle ellipsometry [33] or scanning angle reflectometry [34]) studies can give quantitative insights regarding the evolu-tion of the axial structure of brushes, i.e.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

2016

Self Cite

View full text Add to dashboard Cite

We describe a microscope-based optical setup that allows us to perform space-and time-resolved measurements of the spectral reflectance of transparent substrates coated with ultrathin films. This technique is applied to investigate the behavior in water of thermosensitive polymer brushes made of poly(N-isopropylacrylamide) grafted on glass. We show that spectral reflectance measurements yield quantitative information about the conformation and axial structure of the brushes as a function of temperature. We study how molecular parameters (grafting density, chain length) affect the hydration state of a brush, and provide one of the few experimental evidence for the occurrence of vertical phase separation in the vicinity of the lower critical solution temperature of the polymer. The origin of the hysteretic behavior of poly(N-isopropylacrylamide) brushes upon cycling the temperature is also clarified. We thus demonstrate that our optical technique allows for in-depth characterization of stimuli-responsive polymer layers, which is crucial for the rational design of smart polymer coatings in actuation, gating or sensing applications.

show abstract

“…Theoretical predictions for h swell [44,45] allow us to obtain the following expression for the swelling ratio of a brush, as detailed in previous work [24]:…”

Section: B Brush Swelling At Room Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Then, the graft density was shown to influence the brush structure. A high graft density can cause phase separation [121], and more generally the density will modulate the protein adsorption rate within the brushes, as for BSA [44]. Malham et al showed that chain rearrangements over time could slightly increase inter-chain adhesion and related this to −NH and C O hydrogen bonding [121].…”

Section: Smart Bio-surfaces: Example Of Poly(n-isopropylacrylamide) Tmentioning

confidence: 99%

PNIPAM grafted surfaces through ATRP and RAFT polymerization: Chemistry and bioadhesion

Conzatti

Cavalié

Combes

et al. 2017

Colloids and Surfaces B: Biointerfaces

View full text Add to dashboard Cite

a b s t r a c tBiomaterials surface design is critical for the control of materials and biological system interactions. Being regulated by a layer of molecular dimensions, bioadhesion could be effectively tailored by polymer surface grafting. Basically, this surface modification can be controlled by radical polymerization, which is a useful tool for this purpose. The aim of this review is to provide a comprehensive overview of the role of surface characteristics on bioadhesion properties. We place a particular focus on biomaterials functionalized with a brush surface, on presentation of grafting techniques for "grafting to" and "grafting from" strategies and on brush characterization methods. Since atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization are the most frequently used grafting techniques, their main characteristics will be explained. Through the example of poly(N-isopropylacrylamide) (PNIPAM) which is a widely used polymer allowing tuneable cell adhesion, smart surfaces involving PNIPAM will be presented with their main modern applications.

show abstract

“…It is noteworthy that the PNIPAAM brushes may act differently as compared to bulk aqueous solutions since they are constrained by one end to a surface. The dependence of PNIPAAM brush conformation change on different molecular weight and grafting density has been extensively investigated by using a number of experimental techniques including neutron reflectivity (NR), [8][9][10][11] atomic force microscopy (AFM), [12][13][14][15] quartz crystal microbalance measurements (QCM), 12,13,16,17 surface forces, [18][19][20] ellipsometry, 21 water contact angle measurement, 18,19 and surface plasmon resonance (SPR). 22 Generally, the molecular weight and a) Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Modeling lower critical solution temperature behavior of associating polymer brushes with classical density functional theory

Gong

Marshall

Chapman

2013

The Journal of Chemical Physics

View full text Add to dashboard Cite

We study the lower critical solution temperature (LCST) behavior of associating polymer brushes (i.e., poly(N-isopropylacrylamide)) using classical density functional theory. Without using any empirical or temperature-dependent parameters, we find the phase transition of polymer brushes from extended to collapsed structure with increasing temperature, indicating the LCST behavior of polymer brushes. The LCST behavior of associating polymer brushes is attributed to the interplay of hydrogen bonding interactions and Lennard-Jones attractions in the system. The effect of grafting density and molecular weight on the phase behavior of associating polymer brushes has been also investigated. We find no LCST behavior at low grafting density or molecular weight. Moreover, increasing grafting density decreases the LCST and swelling ratio of polymer brushes. Similarly, increasing molecular weight decreases the LCST but increases the swelling ratio. At very high grafting density, a partial collapsed structure appears near the LCST. Qualitatively consistent with experiments, our results provide insight into the molecular mechanism of LCST behavior of associating polymer brushes.

show abstract

Density Effects on Collapse, Compression, and Adhesion of Thermoresponsive Polymer Brushes

Cited by 129 publications

References 54 publications

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

The Conformation of Thermoresponsive Polymer Brushes Probed by Optical Reflectivity

PNIPAM grafted surfaces through ATRP and RAFT polymerization: Chemistry and bioadhesion

Modeling lower critical solution temperature behavior of associating polymer brushes with classical density functional theory

Contact Info

Product

Resources

About