arXiv subjects

Pik-Yin Lai

Publications and source records attributed to Pik-Yin Lai.

23 records · Page 2Linked to original sources

arXiv2009

Optically induced electrostriction modes in a nanoparticle of a uniformly charged electret

The electromagnetic response of a nanoparticle of an ion-doped polymeric elastic insulator, commonly called as an electret, is considered in the continuum model of a uniformly charged elastic sphere. The spectral formulae for the frequency of optically induced spheroidal and torsional shear oscillations driven by bulk force of elastic and dielectric stresses are obtained in analytic form. Particular attention is given to relaxation dielectric mode of the electrostriction response and its stability in the lowest quadrupole mode. The practical usefulness of ultrafine particles of electrets as a biolabels capable of accumulating likely-charged inclusions uniformly dispersed over the spherical volume of an elastic matrix is briefly discussed.

cond-mat.mtrl-sci↗

arXiv2005

Conformational Properties of an Adsorbed Charged Polymer

The behavior of a strongly charged polymer adsorbed on an oppositely charged surface of low-dielectric constant is formulated by the functional integral method. By separating the translational, conformational, and fluctuational degrees of freedom, the scaling behaviors for both the height of the polymer and the thickness of the diffusion layer are determined. Unlike the results predicted by scaling theory, we identified the continuous crossover from the weak compression to the compression regime. All teh analytical results are found to be consistent with Monte-Carlo simulations. Finally, an alternative (operational) definition of a charged polymer adsorption is proposed.

cond-mat.soft↗

arXiv2004

Scaling Theory of Polyelectrolyte Adsorption on Repulsive Charged Surface

We studied polyelectrolyte adsorption on a repulsive charged surface by scaling analysis. At low ionic strength and low surface charge density in which a single polyelectrolyte is able to be adsorbed onto the surface, different regimes in the phase diagram are identified. The possibility of multi-layer structure formed by polyelectrolytes of like charge is also investigated.

cond-mat.soft↗

arXiv2004

Adsorption Transition of a Polyelectrolyte on a High-dielectric Charged Substrate

The behavior of a polyelectrolyte adsorbed on a charged surface of high-dielectric constant is studied by both Monte-Carlo simulation and analytical methods. It is found that in a low ionic strength medium, the transition is first-order with the repulsive charged surface. The order parameter which characterize the polyelectrolyte adsorption, the surface monomer density, follows a linear relation with surface charge density. It indicates the polyelectrolyte is always compressed on the substrate. No conformation change exists before the de-sorption. Finally, a new scaling law for the layer thickness is derived and verified by the simulation data.

cond-mat.soft↗

arXiv2003

Polyelectrolyte Adsorption on Charged Substrate

The behavior of a polyelectrolyte adsorbed on a charged substrate of high-dielectric constant is studied by both Monte-Carlo simulation and analytical methods. It is found that in a low enough ionic strength medium, the adsorption transition is first-order where the substrate surface charge still keeps repulsive. The monomer density at the adsorbed surface is identified as the order parameter. It follows a linear relation with substrate surface charge density because of the electrostatic boundary condition at the charged surface. During the transition, the adsorption layer thickness remains finite. A new scaling law for the layer thickness is derived and verified by simulation.

cond-mat.soft↗