Semi-flexible hydrogen-bonded and non-hydrogen bonded lattice polymers

Abstract

We investigate the addition of stiffness to the lattice model of hydrogen-bonded polymers in two and three dimensions. We find that, in contrast to polymers that interact via a homogeneous short-range interaction, the collapse transition is unchanged by any amount of stiffness: this supports the physical argument that hydrogen bonding already introduces an effective stiffness. Contrary to possible physical arguments, favouring bends in the polymer does not return the model's behaviour to that comparable to the semi-flexible homogeneous interaction model, where the canonical $\theta$-point occurs for a range of parameter values. In fact, for sufficiently large bending energies the crystal phase disappears altogether, and no phase transition of any type occurs. We also compare the order-disorder transition from the globule phase to crystalline phase in the semi-flexible homogeneous interaction model to that for the fully-flexible hybrid model with both hydrogen and non-hydrogen like interactions. We show that these phase transitions are of the same type and are a novel polymer critical phenomena in two dimensions. That is, it is confirmed that in two dimensions this transition is second-order, unlike in three dimensions where it is known to be first order. We also estimate the crossover exponent and show that there is a divergent specific heat, finding $\varphi =0.7(1)$ or equivalently $\alpha =0.6(2)$. This is therefore different from the $\theta$ transition, for which $\alpha =-1/3$.

References in corpus (6)

• Phase Transitions of Single Semi-stiff Polymer Chains
• The effect of chain stiffness on the phase behaviour of isolated homopolymers
• Freezing and Collapse of Flexible Polymers on Regular Lattices in Three Dimensions
• Two dimensional self-avoiding walk with hydrogen-like bonding: Phase diagram and critical behaviour
• Continuous melting of compact polymers
• The competition of hydrogen-like and isotropic interactions on polymer collapse

Cited by in corpus (7)

• Identification of a polymer growth process with an equilibrium multi-critical collapse phase transition: the meeting point of swollen, collapsed and crystalline polymers
• Stiffness dependence of critical exponents of semiflexible polymer chains situated on two-dimensional compact fractals
• Semi-flexible compact polymers in two dimensional nonhomogeneous confinement
• Polymer collapse of a self-avoiding trail model on a two-dimensional inhomogeneous lattice
• Lattice polymers with two competing collapse interactions
• A semi-flexible attracting-segment model of three-dimensional polymer collapse
• Effect of lattice inhomogeneity on collapsed phases of semi-stiff ISAW polymers