Design of Functionalized Lobed Particles for Porous Self-Assemblies

Biswajit Gorai,Harish Vashisth,Brunno C Rocha

doi:10.1007/s11837-021-04715-w

Abstract

Colloidal particles fabricated with anisotropic interactions have emerged as building blocks for designing materials with various nanotechnological applications. We used coarse-grained Langevin dynamics simulations to probe the morphologies of self-assembled structures formed by lobed particles decorated with functional groups. We tuned the interactions between the functional groups to investigate their effect on the porosity of self-assembled structures formed by lobed particles with different shapes (snowman, dumbbell, trigonal planar, tetrahedral, square planar, trigonal bipyramidal, and octahedral) at different temperatures. The dumbbell, trigonal planar, and square planar shaped particles, with planar geometries, form self-assembled structures including elongated chains, honeycomb sheets, and square sheets, respectively. The particles with non-planar geometries (tetrahedral, trigonal bipyramidal, and octahedral) self-assemble into random aggregate morphologies. The structures formed by trigonal bipyramidal and octahedral particles exhibit smaller and homogeneous pores compared to the structures formed by trigonal planar and square planar particles. The porosity in self-assembled structures is substantially enhanced by the functionalization of particles.

Highlights

IntroductionColloids with anisotropic interactions are the nanoscopic building blocks for self-assembly into complex structures with distinct morphologies.[1,2,3,4,5,6,7,8,9,10,11] The bottom-up technique of colloidal self-assembly facilitates the formation of well-defined superstruc-(Received February 20, 2021; accepted April 26, 2021; published online June 1, 2021)tures by controllable and site-specific interactions.[12,13,14,15,16] The efforts to design building blocks with anisotropic properties have seen a transition in the architecture of spherical patchy particles from two-faced Janus colloids to multiblock colloidal particles.[17]
In another work,[49] we studied the influence of the lobe size and temperature on the porosity and morphology of the self-assembled superstructures formed by five different types of lobed particles of different shapes
We observed that the functionalized lobed particles self-assembled into distinct morphologies including cylindrical aggregates, elongated chains, honeycomb aggregates, honeycomb sheets, random aggregates, and square sheets, except the SS1M particles that exist in a dissociated state at all simulation conditions

Summary

Introduction

Colloids with anisotropic interactions are the nanoscopic building blocks for self-assembly into complex structures with distinct morphologies.[1,2,3,4,5,6,7,8,9,10,11] The bottom-up technique of colloidal self-assembly facilitates the formation of well-defined superstruc-(Received February 20, 2021; accepted April 26, 2021; published online June 1, 2021)tures by controllable and site-specific interactions.[12,13,14,15,16] The efforts to design building blocks with anisotropic properties have seen a transition in the architecture of spherical patchy particles from two-faced Janus colloids to multiblock colloidal particles.[17]. The poly(vinyl alcohol) hydrogels are biocompatible and possess stable mechanical characteristics at a broad range of temperatures and pH.[22,23,24,25] Rossi et al.[26] synthesized polymeric hydrogels functionalized with biodegradable nanoparticles to achieve a hydrogel matrix useful for controlled drug delivery. The non-toxic b-peptide hydrogels self-assembled in aqueous solvent to form a mechanically stable and biocompatible matrix with enhanced self-healing property.[27] The hydrogels are functionally tailored using proteins, nucleotides, polymers, nanoparticles, and chemical scaffolds to facilitate the formation of extracellular matrix for biological applications.[28,29,30,31,32] The swelling/deswelling during dispersion and emulsion polymerization-based techniques are tuned by various external stimuli to synthesize hydrogel colloids.[33] For example, the poly(N-isopropylacrylamide)-based microgel colloids are functionalized with different groups to develop characteristic features for versatile applications.[34]

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Results

Conclusion