Intramolecular phase separation of copolymer "bottle brushes": No sharp phase transition but a tunable length scale

We study bottlebrush macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and dynamic light scattering (DLS). These polymers consist of a linear backbone to which long side chains are chemically grafted. The backbone contains about 1600 monomer units (weight average) and every second monomer unit carries side-chains with ca. 60 monomer units. The SLS- and SANS data extrapolated to infinite dilution lead to the form factor o...

We study the conformational properties of heteropolymers containing two types of monomers A and B, modeled as self-avoiding random walks on a regular lattice. Such a model can describe in particular the sequences of hydrophobic and hydrophilic residues in proteins (K.F. Lau and K.A. Dill, Macromolecules {\bf 22}, 3986 (1989)) and polyampholytes with oppositely charged groups (Y. Kantor and M. Kardar, Europhys. Lett.{\bf 28}, 169 (1994)). Treating the sequences of the two type...

Molecular dynamics simulations are used to study the phase behavior of a single linear multiblock copolymer with blocks of A- and B-type monomers under poor solvent conditions, varying the block length $N$, number of blocks $n$, and the solvent quality (by variation of the temperature $T$). The fraction $f$ of A-type monomers is kept constant and equal to 0.5, and always the lengths of A and B blocks were equal ($N_{A}=N_{B}=N$), as well as the number of blocks ($n_{A}=n_{B}=...

Molecular Dynamics simulations of a coarse-grained bead-spring model of flexible macromolecules tethered with one end to the surface of a cylindrical pore are presented. Chain length $N$ and grafting density $\sigma$ are varied over a wide range and the crossover from ``mushroom'' to ``brush'' behavior is studied for three pore diameters. The monomer density profile and the distribution of the free chain ends are computed and compared to the corresponding model of polymer bru...

A coarse grained model for flexible polymers end-grafted to repulsive spherical nanoparticles is studied for various chain lengths and grafting densities under good solvent conditions, by Molecular Dynamics methods and density functional theory. With increasing chain length the monomer density profile exhibits a crossover to the star polymer limit. The distribution of polymer ends and the linear dimensions of individual polymer chains are obtained, while the inhomogeneous str...

The absorption of free linear chains in a polymer brush was studied with respect to chain size $L$ and compatibility $\chi$ with the brush by means of Monte Carlo (MC) simulations and Density Functional Theory (DFT) / Self-Consistent Field Theory (SCFT) at both moderate, $\sigma_g = 0.25$, and high, $\sigma_g = 1.00$, grafting densities using a bead-spring model. Different concentrations of the free chains $0.0625 \le \phi_o \le 0.375$ are examined. Contrary to the case of $\...

Polymer bottlebrushes provide intriguing features being relevant both in nature and in synthetic systems. While their presence in the articular cartilage optimizes synovial joint lubrication, bottlebrushes offer pathways for fascinating applications, such as within super- soft elastomers or for drug delivery. However, the current theoretical understanding lacks completeness, primarily due to the complicated interplay of many length scales. Herein, we develop an analytical mod...

The stretching of brushes of long polymers grafted to a planar surface is investigated byMonte Carlo simulations in the limit of very high grafting densities, as achieved in recent experiments. The monomer density profiles are shown to deviate considerably from the parabolic limiting form predicted by self-consistent field theory. A rapid transition is observed from parabolic to fully stretched polymers, characterized by a dramatic change in the end-monomer height distributio...

The scission kinetics of bottle-brush molecules in solution and on an adhesive substrate is modeled by means of Molecular Dynamics simulation with Langevin thermostat. Our macromolecules comprise a long flexible polymer backbone with $L$ segments, consisting of breakable bonds, along with two side chains of length $N$, tethered to each segment of the backbone. In agreement with recent experiments and theoretical predictions, we find that bond cleavage is significantly enhance...

We study a single self avoiding hydrophilic hydrophobic polymer chain, through Monte Carlo lattice simulations. The affinity of monomer $i$ for water is characterized by a (scalar) charge $\lambda_{i}$, and the monomer-water interaction is short-ranged. Assuming incompressibility yields an effective short ranged interaction between monomer pairs $(i,j)$, proportional to $(\lambda_i+\lambda_j)$. In this article, we take $\lambda_i=+1$ (resp. ($\lambda_i=- 1$)) for hydrophilic ...