A5068153815- Electrostatics and Colloid Interactions
- Material Dynamics and Properties
- Surfactants and Colloidal Systems
- Micro and Nano Robotics
- Spectroscopy and Quantum Chemical Studies
- Nanopore and Nanochannel Transport Studies
- Advanced biosensing and bioanalysis techniques
- Block Copolymer Self-Assembly
- Polymer Surface Interaction Studies
- Supramolecular Self-Assembly in Materials
- DNA and Nucleic Acid Chemistry
- Lipid Membrane Structure and Behavior
- Gold and Silver Nanoparticles Synthesis and Applications
- Pickering emulsions and particle stabilization
- Advanced Materials and Mechanics
- Hydrogels: synthesis, properties, applications
- Advanced Polymer Synthesis and Characterization
- Microfluidic and Bio-sensing Technologies
- Theoretical and Computational Physics
- Modular Robots and Swarm Intelligence
- Electrochemical Analysis and Applications
- Bacteriophages and microbial interactions
- Rheology and Fluid Dynamics Studies
- Protein Structure and Dynamics
- nanoparticles nucleation surface interactions
Northwestern University
2016-2025
Centre Hospitalier Universitaire Sainte-Justine
2024
Université de Montréal
2024
Materials Science & Engineering
2009-2023
Texas State University
2023
Northwestern University
2021
International Institute for Nanotechnology
2012-2019
Argonne National Laboratory
2015
IPM Institute of North America
2010-2014
Division of Chemistry
2013-2014
The chemical variety present in the organic electronics literature has motivated us to investigate potential nonbonding interactions often incorporated into conformational "locking" schemes. We examine a of interactions, including oxygen-sulfur, nitrogen-sulfur, and fluorine-sulfur, using accurate quantum-chemical wave function methods noncovalent interaction (NCI) analysis on selection high-performing conjugated polymers small molecules found literature. In addition, we evaluate set...
The influence of the number-average molecular weight (Mn) on blend film morphology and photovoltaic performance all-polymer solar cells (APSCs) fabricated with donor polymer poly[5-(2-hexyldodecyl)-1,3-thieno[3,4-c]pyrrole-4,6-dione-alt-5,5-(2,5-bis(3-dodecylthiophen-2-yl)thiophene)] (PTPD3T) acceptor poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2); N2200) is systematically investigated. Mn effect analysis both PTPD3T...
Mimicking the designs found in proteins Natural combine a range of useful features, including chemical diversity, ability to rapidly switch between preprogrammed shapes, and hierarchy structures. Panganiban et al. designed random copolymers with polar nonpolar groups, using many features (see Perspective by Alexander-Katz Van Lehn). Their structures could serve as “broad spectrum” surfactants, able promote solubilization organic solvents help preserve functionality aqueous environments....
Reconfiguring and programming the action of a magnetically driven robot using light.
With the abundant variety and increasing chemical complexity of conjugated polymers proliferating field organic semiconductors, it has become increasingly important to correlate polymer molecular structure with its mesoscale conformational morphological attributes. For instance, is unknown which combinations moieties periodicities predictably produce ordering. Interestingly, not all ordered morphologies result in efficient devices. In this work we have parametrized accurate classical...
Covalent organic framework (COF) membranes are of great promise for energy-efficient separations. Thick, polycrystalline COF films have been reported to separate dyes, salts, bacteria, and nanoparticles on the basis size-selective transport through ordered pores. Here, we show that these materials function as adsorbents, not size-sieving membranes. Binding isotherms several dyes typical membrane literature three powder samples illustrate COFs high-capacity adsorbents with affinities span a...
Colloidal nanocrystals of metals, semiconductors, and other functional materials can self-assemble into long-range ordered crystalline quasicrystalline phases, but insulating organic surface ligands prevent the development collective electronic states in nanocrystal assemblies. We reversibly self-assembled colloidal gold, platinum, nickel, lead sulfide, selenide with conductive inorganic supercrystals exhibiting optical properties consistent strong coupling between constituent nanocrystals....
Solutions of highly charged polyelectrolyte chains are described by a model that introduces ion condensation as random charge along the polymer. The degree is obtained solving Poisson–Boltzmann equation with cylindrical geometry. Short range electrostatic attractions between monomers via condensed counterions high enough valency lead to reversible chain precipitation. polymer concentration over which salt-free solutions unstable determined, well miscibility when salt added. Redissolution at...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory of microphase separation in graft and star copolymersMonica Olvera de la Cruz Isaac C. SanchezCite this: Macromolecules 1986, 19, 10, 2501–2508Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/ma00164a008https://doi.org/10.1021/ma00164a008research-articleACS PublicationsRequest reuse permissionsArticle Views1212Altmetric-Citations259LEARN...
The mechanical properties of self-assembled fibrillar networks are influenced by the specific intermolecular interactions that modulate fiber entanglements. We investigate how changing these influences mechanics nanofiber gels composed peptide amphiphile (PA) molecules. PAs developed in our laboratory self-assemble into nanofibers after neutralization or salt-mediated screening charged residues their segment. report here on gelation, stiffness, and response to deformation formed from a...
The collapse of flexible polyelectrolytes in a solution multivalent counterions is studied by means two state model. states correspond to rodlike and spherically collapsed conformations. We focus on the very dilute monomer concentration regime where transition found occur when charge salt comparable (but smaller) that monomers. main contribution free energy conformation linear number monomers N, since internal polymer approaches an amorphous ionic solid. grows as N ln due electrostatic...
We study the self-assembly of peptide amphiphile (PA) molecules, which is governed by hydrophobic interactions between alkyl tails and a network hydrogen bonds blocks. demonstrate that interplay these two results in formation assemblies different morphology, particular, single beta-sheets connected laterally bonds, stacks parallel beta-sheets, spherical micelles, micelles with corona, long cylindrical fibers. characterize size distribution aggregates as function molecular interactions. Our...
The microphase separation transition for asymmetric triblock and (A–B)m star copolymer melts is investigated following a mean-field approach proposed by Leibler diblock melts. Continuous transitions are found in all architectures stars any m at some composition fc. phase diagram the equilibrium morphologies notably altered varying architecture of copolymers.
We develop a detailed molecular theory that describes the response of weak polyelectrolyte gels to changes in both pH and salt concentration, c, solution. This approach includes specific details conformational degrees freedom polymeric gel, acid−base equilibrium, solution entropy as well electrostatic, van der Waals, excluded-volume interactions. Here, we study polyacid good solvent. The physical properties gel are found depend on coupling between charge regulation In particular, gel's...
We use molecular dynamics simulations to study the crystallization of spherical nucleic-acid (SNA) gold nanoparticle conjugates, guided by sequence-specific DNA hybridization events. Binary mixtures SNA conjugates (inorganic core diameter in 8-15 nm range) are shown assemble into BCC, CsCl, AlB(2), and Cr(3)Si crystalline structures, depending upon particle stoichiometry, number immobilized strands per particle, sequence length, hydrodynamic size ratio involved crystallization. These data...
Skeletal muscle provides inspiration on how to achieve reversible, macroscopic, anisotropic motion in soft materials. Here we report the bottom-up design of macroscopic tubes that exhibit actuation driven by a thermal stimulus. The tube is built from hydrogel which extremely long supramolecular nanofibers are aligned using weak shear forces, followed radial growth thermoresponsive polymers their surfaces. hierarchically ordered exhibits reversible with changes temperature, much greater...
The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein plays a crucial role in binding human cell receptor ACE2 that is required for viral entry. Many studies have been conducted to target structures RBD-ACE2 and design RBD-targeting vaccines drugs. Nevertheless, mutations distal from RBD also impact its transmissibility antibody can non-RBD regions, suggesting incomplete region protein-ACE2 binding. Here, order elucidate distant mechanisms, we analyze complexes with wild-type key...
A versatile method for the design of colloidal crystals involves use DNA as a particle-directing ligand. With such systems, DNA-nanoparticle conjugates are considered programmable atom equivalents (PAEs), and rules have been devised to engineer crystallization outcomes. This work shows that when reduced in size grafting density, PAEs behave electron (EEs), roaming through stabilizing lattices defined by larger PAEs, electrons do metals classical picture. discovery defines new property...