Charge-dipole Interactions Research Articles

Observation of a core-excited dipole-bound state ∼1eV above the electron detachment threshold in cryogenically cooled acetylacetonate.

Dipole-bound states in anions exist when a polar neutral core binds an electron in a diffuse orbital through charge-dipole interaction. Electronically excited polar neutral cores can also bind an electron in a diffuse orbital to form Core-Excited Dipole-Bound States (CE-DBSs), which are difficult to observe because they usually lie above the electron detachment threshold, leading to very short lifetimes and, thus, unstructured transitions. We report here the photodetachment spectroscopy of cryogenically cooled acetylacetonate anion (C5H7O2-) recorded by detecting the neutral radical produced upon photodetachment and the infrared spectroscopy in He-nanodroplets. Two DBSs were identified in this anion. One of them lies close to the electron detachment threshold (∼2.74eV) and is associated with the ground state of the radical (D0-DBS). Surprisingly, the other DBS appears as resonant transitions at 3.69eV and is assigned to the CE-DBS associated with the first excited state of the radical (D1-DBS). It is proposed that the resonant transitions of the D1-DBS are observed ∼1eV above the detachment threshold because its lifetime is determined by the internal conversion to the D0-DBS, after which the fast electron detachment takes place.

Ion induced nucleation of charged droplets enhanced by external electric field

The nucleation theory of charged particles in an external electric field environment is considered. The Gibbs free energy and nucleation rate changes of ion-induced nucleation under an external electric field are studied. The Classical Kelvin–Thomson equation and the ion-induced nucleation theory in the external electric field environment are corrected. The results show that the presence of an electric field can reduce the Gibbs free energy of nucleation and increase the nucleation rate. For particles larger than a few nanometers in size, the impact of the external electric field on reducing the condensation saturation ratio is more pronounced than the combined influence of the Thomson effect and dipole–charge interaction.

Influence of image forces on charge-dipole interaction in two-layered systems.

Interaction between a fixed point electric charge Q and a freely rotating point electric dipole with the magnitude P pinned near a plane interface between two dispersionless insulators with different dielectric permittivities ɛ1 and ɛ2 has been considered. It was shown that, as a result of this interaction and the interaction of the dipole with the polarization charges induced at the interface by the charge Q and the dipole itself, there arise regions where the dipole can possess either one or two equilibrium orientations. The spatial distributions of the electrostatic dipole energy Wtotal under the combined action of the charge Q and the induced interface polarization charges, as well as the equilibrium dipole orientations (orientation maps), the boundaries between the regions with different numbers of dipole orientations, and their evolution with the variation of problem parameters (the charge and dipole magnitudes, the mismatch between ɛ1 and ɛ2, and the charge-interface distance) were calculated. It was shown that there can emerge local minima of Wtotal, which may play the role of traps for dipoles (in particular, excitons in layered structures), and the corresponding requirements for the problem parameters were found. Most results were obtained in analytical form. The model can be applied to various physical systems, for instance, polar molecules, excitons, and trions in layered structures.

Swimming short fibrous nasal drops achieving intraventricular administration

Adequate drug delivery across the blood–brain barrier (BBB) is a critical factor in treating central nervous system (CNS) disorders. Inspired by swimming fish and the microstructure of the nasal cavity, this study is the first to develop swimming short fibrous nasal drops that can directly target the nasal mucosa and swim in the nasal cavity, which can effectively deliver drugs to the brain. Briefly, swimming short fibrous nasal drops with charged controlled drug release were fabricated by electrospinning, homogenization, the π-π conjugation between indole group of fibers, the benzene ring of leucine-rich repeat kinase 2 (LRRK2) inhibitor along with charge-dipole interaction between positively charged poly-lysine (PLL) and negatively charged surface of fibers; this enabled these fibers to stick to nasal mucosa, prolonged the residence time on mucosa, and prevented rapid mucociliary clearance. In vitro, swimming short fibrous nasal drops were biocompatible and inhibited microglial activation by releasing an LRRK2 inhibitor. In vivo, luciferase-labelled swimming short fibrous nasal drops delivered an LRRK2 inhibitor to the brain through the nasal mucosa, alleviating cognitive dysfunction caused by sepsis-associated encephalopathy by inhibiting microglial inflammation and improving synaptic plasticity. Thus, swimming short fibrous nasal drops is a promising strategy for the treatment of CNS diseases.

Opposite Effects of the Rotational and Translational Energy on the Rates of Ion-Molecule Reactions near 0 K: The D2++NH3 and D2++ND3 Reactions

The ion-molecule reactions D2++NH3 and D2++ND3 are studied at low collision energies (Ecoll from zero to approximately kB×50 K), with the D2+ ions in the ground rovibrational state and for different rotational temperatures of the ammonia molecules, using the Rydberg-Stark merged-beam approach. Two different rotational temperatures (approximately 15 K and approximately 40 K), measured by (2+1) resonance-enhanced multiphoton-ionization spectroscopy, are obtained by using a seeded supersonic expansion in He and a pure ammonia expansion, respectively. The experimental data reveal a strong enhancement of the rate coefficients at the lowest collision energies caused by the charge-dipole interaction. Calculations based on a rotationally adiabatic capture model accurately reproduce the observed kinetic-energy dependence of the rate coefficients. The rate coefficients increase with increasing rotational temperature of the ammonia molecules, which contradicts the expectation that rotational excitation should average the dipoles out. Moreover, these reactions exhibit a pronounced inverse kinetic isotope effect. The difference is caused by nuclear-spin-statistical factors and the smaller rotational constants and tunneling splittings in ND3. Published by the American Physical Society 2024

Reaction mechanisms in hydrated magnesium silicate glass investigated by Ab-Initio methods and Metadynamics

In the field of magnesium-containing silicate glass alteration under aqueous conditions, enstatite glass (MgSiO3) is used as a valuable system to investigate reaction pathways occurring in its hydrated form by means of Ab-Initio methods. In contrast to previous dissolution studies in which the water molecules interacted only at the glass surface or with small molecular clusters, here we follow reaction pathways for water molecules introduced in the voids of a realistic glass structure. Metadynamics combined with atomic charges derived from electrostatic potential suggest that water dissociation follows a two-step scheme: at first, the water molecule interacts with a SiO4 or MgOx(x≥3) structural unit via dipole–dipole or dipole–charge interactions, and second, a proton transfer occurs. It also appears that SiOH-Mg hydrolysis reactions are the more likely to occur. Furthermore, it is inferred that pathways exist for complete H2O dissociation in two H+ and one O2− ions, leading to new bonding between the free oxygen ion and Si or Mg cations forming the network. This phenomenon could probably counterbalance hydrolysis and depolymerization by increasing again network connectivity. Several bond dissociation energies are evaluated and the MgO bond dissociation enthalpy from the MgOHSi linkage is derived to be 1.34 eV (or 128.84 kJ mol−1).

Turning gas hydrate nucleation with oxygen-containing groups on size-selected graphene oxide flakes

Gas hydrate is a promising alternative for gas capture and storage due to its high gas storage capacity achieved with only structured water molecules. Nucleation is the critical controlling step in gas hydrate formation. Adding an alien solid surface is an effective approach to regulate gas hydrate nucleation. However, how the solid surface compositions control the gas hydrate nucleation remains unclear. Benefiting from the fact that the surface compositions of graphene oxide (GO) can be finely tuned, we report the effect of functional groups of size-selected GO flakes on methane hydrate nucleation. The carbonyl and carboxyl of GO flakes showed a more prominent promotion for methane hydrate nucleation than the hydroxyl of GO flakes. Surface energy, zeta potential, Raman spectra, and molecular dynamics simulation analysis were used to reveal the regulation mechanism of the functional groups of size-selected GO flakes on methane hydrate nucleation. The GO flakes with abundant carbonyl and carboxyl exhibited higher charge density than those enriched in hydroxyl. The negatively charged GO flakes can induce water molecules to form an ordered hydrogen-bonded arrangement via charge-dipole interactions. Therefore, the water molecules surrounding the carboxyl and carbonyl showed a more ordered hydrogen-bonded structure than those around the hydroxyl of GO flakes. The ordered water arrangement, similar to methane hydrate cages, significantly accelerated methane hydrate nucleation. Our study shows how the surface chemistry of solids control gas hydrate nucleation and sheds light on the design of effective heterogeneous nucleators for gas hydrate.

Probing Dipole-Bound States Using Photodetachment Spectroscopy and Resonant Photoelectron Imaging of Cryogenically Cooled Anions.

Molecular anions with polar neutral cores can support highly diffuse dipole-bound states below their detachment thresholds due to the long-range charge-dipole interaction. Such nonvalence states constitute a special class of excited electronic states for anions and were observed in early photodetachment experiments to measure the electron affinities of organic radicals. Recent experimental advances, in particular, the ability to create cold anions using a cryogenically cooled Paul trap, have allowed the investigation of dipole-bound excited states at a new level. For the first time, the zero-point level of dipole-bound excited states can be observed via resonant two-photon detachment, and resonant photoelectron spectroscopy can be performed via the above-threshold vibrational levels (Feshbach resonances) of the dipole-bound states. This Perspective describes recent progress in the investigation of dipole-bound states in the authors' lab using an electrospray photoelectron spectroscopy apparatus equipped with a cryogenically cooled Paul trap and high-resolution photoelectron imaging.

Observation of Rydberg Blockade Due to the Charge-Dipole Interaction between an Atom and a Polar Molecule.

We demonstrate Rydberg blockade due to the charge-dipole interaction between a single Rb atom and a single RbCs molecule confined in optical tweezers. The molecule is formed by magnetoassociation of a Rb+Cs atom pair and subsequently transferred to the rovibrational ground state with an efficiency of 91(1)%. Species-specific tweezers are used to control the separation between the atom and molecule. The charge-dipole interaction causes blockade of the transition to the Rb(52s) Rydberg state, when the atom-molecule separation is set to 310(40)nm. The observed excitation dynamics are in good agreement with simulations using calculated interaction potentials. Our results open up the prospect of a hybrid platform where quantum information is transferred between individually trapped molecules using Rydberg atoms.

Engineering Single-Atom Electrocatalysts for Enhancing Kinetics of Acidic Volmer Reaction.

The design of active and low-cost electrocatalyst for hydrogen evolution reaction (HER) is the key to achieving a clean hydrogen energy infrastructure. The most successful design principle of hydrogen electrocatalyst is the activity volcano plot, which is based on Sabatier principle and has been used to understand the exceptional activity of noble metal and design of metal alloy catalysts. However, this application of volcano plot in designing single-atom electrocatalysts (SAEs) on nitrogen doped graphene (TM/N4C catalysts) for HER has been less successful due to the nonmetallic nature of the single metal atom site. Herein, by performing ab initio molecular dynamics simulations and free energy calculations on a series of SAEs systems (TM/N4C with TM = 3d, 4d, or 5d metals), we find that the strong charge-dipole interaction between the negatively charged *H intermediate and the interfacial H2O molecules could alter the transition path of the acidic Volmer reaction and dramatically raise its kinetic barrier, despite its favorable adsorption free energy. Such kinetic hindrance is also experimentally confirmed by electrochemical measurements. By combining the hydrogen adsorption free energy and the physics of competing interfacial interactions, we propose a unifying design principle for engineering the SAEs used for hydrogen energy conversion, which incorporates both thermodynamic and kinetic considerations and allows going beyond the activity volcano model.

PH-dependent self-assembly mechanism of a single repetitive domain from a spider silk protein

Spider silk is self-assembled from full-length silk proteins, and some silk protein fragments can also form silk-like fibers in vitro. However, the mechanism underlying the silk fiber formation is not understood well. In this study, we investigated the fiber formation of a single repetitive domain (RP) from a minor ampullate silk protein (MiSp). Our findings revealed that pH and salt concentration affect not only the stability of MiSp-RP but also its self-assembly into fibers and aggregates. Using nuclear magnetic resonance (NMR) spectroscopy, we solved the three-dimensional (3D) structure of MiSp RP in aqueous solution. On the basis of the structure and mutagenesis, we revealed that charge-dipole interactions are responsible for the pH- and salt-dependent properties of MiSp-RP. Our results indicate that fiber formation is regulated by a delicate balance between intermolecular and intramolecular interactions, rather than by the protein stability alone. These findings have implications for the design of silk proteins for mass production of spider silk.

Effect of protein-starch interactions on starch retrogradation and implications for food product quality.

Starch retrogradation is a consequential part of food processing that greatly impacts the texture and acceptability of products containing both starch and proteins, but the effect of proteins on starch retrogradation has only recently been explored. With the increased popularity of plant-based proteins in recent years, incorporation of proteins into starch-based products is more commonplace. These formulation changes may have unforeseen effects on ingredient functionality and sensory outcomes of starch-containing products during storage, which makes the investigation of protein-starch interactions and subsequent impact on starch retrogradation and product quality essential. Protein can inhibit or promote starch retrogradation based on its exposed residues. Charged residues promote charge-dipole interactions between starch-bound phosphate and protein, hydrophobic groups restrict amylose release and reassociation, while hydrophilic groups impact water/molecular mobility. Covalent bonds (disulfide linkages) formed between proteins may enhance starch retrogradation, while glycosidic bonds formed between starch and protein during high-temperature processing may limit starch retrogradation. With these protein-starch interactions in mind, products can be formulated with proteins that enhance or delay textural changes in starch-containing products. Future work to understand the impact of starch-protein interactions on retrogradation should focus on integrating the fields of proteomics and carbohydrate chemistry. This interdisciplinary approach should result in better methods to characterize mechanisms of interaction between starch and proteins to optimize their food applications. This review provides useful interpretations of current literature characterizing the mechanistic effect of protein on starch retrogradation.

Nonlocal drag thermoelectricity generated by ferroelectric van der Waals heterostructures

The \textquotedblleft ferron\textquotedblright\ excitations of the electric-dipolar order carry energy as well as electric dipoles. Here we predict a nonlocal ferron drag effect in a ferroelectric on top of a metallic film: An electric current in the conductor generates a heat current in the ferroelectric by long-range charge-dipole interactions. The non-local Peltier and its reciprocal Seebeck effect can be controlled by electric gates and detected thermographically. We predict large effects for van der Waals ferroelectric films on graphene.

Charge-controlled Pd catalysis enables the meta-C–H activation and olefination of arenes

The regioselective C-H activation of arenes remains one of the most promising techniques for accessing highly important functionalized motifs. Such functionalizations can generally be achieved through directed and non-directed processes. The directed approach requires a covalently attached directing group (DG) on the substrate to induce reactivity and selectivity and therefore intrinsically leaves a functional group at the point of attachment within the molecule, even after the tailored DG has been removed. Conversely, non-directed methods typically suffer from regioselectivity issues, especially for unbiased substrates. Herein, we report a unique approach that employs weak charge-charge and charge-dipole interactions to enable the meta-selective activation and olefination of arenes to address these challenges in Pd catalysis. The charged moiety can easily be converted to uncharged simple arenes by hydrogenation or cross-coupling. In-depth mechanistic studies prove that the charge is responsible for the observed selectivity. We expect our studies to be generalizable and thereby enable further regioselective transformations.

Distal meta-alkenylation of formal amines enabled by catalytic use of hydrogen-bonding anionic ligands

•Distal C–H activation mediated by non-covalent interactions •Catalytic amount of anionic ligand induces H-bonding interaction with amides •H bonding enables Pd-catalyzed distal meta-activation •Amines with variable linker lengths are susceptible to this protocol Regioselective and site-selective functionalization of distal C–H bonds has remained a significant challenge over the last decades. Although covalently attached directing groups have been designed to help solve this puzzle, their profound impact on step economy significantly hinders the protocol’s applicability. Weak non-covalent interactions have been developed to overcome this, but they have mainly been explored with Ir catalysis. Herein, we aim to execute a Pd-catalyzed meta-selective C–H functionalization of simple amines by harnessing weak non-covalent interactions between an anionic ligand and neutral substrate. A catalytic amount of organic salt acts as a suitable ligand for efficient meta-selective C–H olefination. Experimental and computational studies suggest that site selectivity is governed by the key H-bonding interaction between an anionic donating ligand and neutral motifs. The protocol can be further extended to amines with variable linker lengths, outlining the versatility and applicability of our methodology, while utilizing only a catalytic amount of directing ligand for the transformation. Regioselective and site-selective functionalization of distal C–H bonds has remained a significant challenge over the last decades. Although covalently attached directing groups have been designed to help solve this puzzle, their profound impact on step economy significantly hinders the protocol’s applicability. Weak non-covalent interactions have been developed to overcome this, but they have mainly been explored with Ir catalysis. Herein, we aim to execute a Pd-catalyzed meta-selective C–H functionalization of simple amines by harnessing weak non-covalent interactions between an anionic ligand and neutral substrate. A catalytic amount of organic salt acts as a suitable ligand for efficient meta-selective C–H olefination. Experimental and computational studies suggest that site selectivity is governed by the key H-bonding interaction between an anionic donating ligand and neutral motifs. The protocol can be further extended to amines with variable linker lengths, outlining the versatility and applicability of our methodology, while utilizing only a catalytic amount of directing ligand for the transformation. Charge-controlled Pd catalysis enables the meta-C–H activation and olefination of arenesMondal et al.ChemJanuary 24, 2023In Briefvan Gemmeren and co-workers report a method that enables the meta-selective olefination of arenes on the basis of a charge-controlled Pd-catalyzed C–H activation. The method relies on charge-charge and charge-dipole interactions to achieve unconventional regioselectivities. Mechanistic investigations support this novel means of controlling regioselectivity in Pd-catalyzed C–H activation. A broad scope of functionalized benzyl ammonium products can be accessed, and these are shown to be valuable linchpins for further functionalization toward densely functionalized arenes with challenging substitution patterns. Full-Text PDF Open Access

Energetics and mechanism of complexation between β-lactoglobulin and oligochitosan

β-lactoglobulin–oligochitosan (MW 9500 Da) system was studied under conditions of protein-polysaccharide incompatibility, the dipole-charge, and charge-charge protein-polysaccharide interactions at pH 3.0, 5.5, and 6.0, respectively, using ITC, DSC, and DLS. At pH 5.5 and 6.0, the ITC data revealed a complex formation between β-lactoglobulin and oligochitosan. The binding curves of the protein to the polysaccharide were obtained. The binding parameters, namely, the number of sites ( n ) and the binding constant ( K b ), were estimated in terms of the Langmuir equation. These are n = 2.8 ± 0.1 and K b = 10 6.4±0.1 M −1 at рН 5.5, while n = 1.5 ± 0.1 and K b = 10 5.6±0.1 M −1 at рН 6.0. At pH 3.0, when both the protein and polysaccharide are positively charged, the denaturation parameters of β-lactoglobulin in the β-lactoglobulin–oligochitosan system and in the absence of the polysaccharide coincide independently of the system composition. Under conditions of the complexation, the denaturation parameters of β-lactoglobulin (the denaturation temperature, enthalpy, entropy, and width) displayed complicated dependences on the oligochitosan content. Their analysis supported by measurements of the diffusion coefficients implied that the conformational stability of β-lactoglobulin in the β-lactoglobulin–oligochitosan complexes was defined by the complex composition and supramolecular structure of oligochitosan. • ⦁BLG conserves its stability under conditions of BLG–OCS thermodynamic incompatibility. • ⦁BLG–OCS complexes are formed at pH ≥ 5.2 by dipole-charge or electrostatic interactions. • ⦁BLG–OCS affinity is enthalpy-driven and unusually high ( K b ∼10 6 M −1 ). • ⦁BLG–OCS complexation stabilizes dimeric or tetrameric forms of bound BLG. ⦁ •Stability of bound BLG decreases at low and increases at high OCS concentrations.

Polarizable Molecular Block Model: Toward the Development of an Induced Dipole Force Field for DNA.

For flexible and highly ionized macromolecules such as DNA, it is important to correctly evaluate the intramolecular polarization in an induced dipole force field. In a proposed polarizable molecular block (PMB) model, a large molecule is divided into several molecular blocks. The atomic charges of the blocks are optimized by using the respective electrostatic potentials (ESPs) on the molecular surface. By using the capped hydrogen removal operation, the total charge of the blocks is controlled exactly to have an integer charge. The atomic polarizabilities of the blocks are optimized by using the respective polarized one-electron potentials that are the differences between ESPs with and without an external test charge. Induced dipole-charge interactions between the blocks are all included, but those interactions within the blocks are strictly excluded. All dipole-dipole interactions are included, but the damping functions are applied to the close dipole-dipole pairs. Several types of damping (simple scaling, exponential, linear, and Gaussian) are evaluated. The validity of the PMB model was verified by using trinucleotide duplexes which have A-, B-, and Z-DNA forms. The reference energies of trinucleotide duplexes including counterions (GGT3Na-ACC3Na, GAC3Na-GTC3Na, and GCG3Na-CGC3Na) are calculated using ωB97XD/aug-cc-pVDZ. All damping types reproduced well the reference interaction energies, dipole moments, and ESPs. Among them, the simple scaling with strong attenuation to 1-2 atomic pairs showed the highest stability against the polarization catastrophe. This study shows that it is possible to develop a high-quality polarizable force field by treating the intramolecular polarization on a block-by-block basis.

Effects of the charge–dipole and charge–quadrupole interactions on the He+ + CO reaction rate coefficients at low collision energies

The reaction between He+ and CO forming He + C+ + O has been studied at collision energies in the range between 0 and k B ⋅ 25 K. These low collision energies are reached by measuring the reaction within the orbit of a Rydberg electron after merging a beam of He(n) Rydberg atoms and a supersonic beam of CO molecules with a rotational temperature of 6.5 K. The capture rate of the reaction drops by about 30% at collision energies below k B ⋅ 5 K. This behavior is analyzed in terms of the long-range charge–dipole and charge–quadrupole interactions using an adiabatic-channel capture model. Although the charge–dipole interaction has an effect on the magnitude of the rate coefficients, the effects of the charge–quadrupole interaction determine the main trend of the collision-energy dependence of the rate coefficients at low collision energies. The drop of the capture rate coefficient at low collision energies is attributed to the negative sign of the quadrupole moment of CO (Q zz = −2.839 D Å) and is caused by the |JM⟩ = |00⟩ and |1 ± 1⟩ rotational states of CO, which represent about 70% of the CO molecules at the rotational temperature of 6.5 K.

Charge-Dipole Attraction as a Surface Interaction between Water Droplets Immersed in Organic Phases.

The dynamic behavior of emulsion droplets during their interactions with one another or with solid surfaces plays a paramount role in their ultimate stability in various applications. While the interaction of oil droplets through a surrounding aqueous phase is well understood, recent studies on the interaction of water droplets through a surrounding pure organic phase showed the presence of an unexplained attraction between water droplets at relatively long ranges. In this research study, we propose fixed-surface-charge-bulk-dipole attraction as a new interaction force between water-in-oil droplets and then derive an equation for its disjoining pressure. The behavior of water droplets in the presence and absence of this charge-dipole interaction was numerically quantified using the Stokes-Reynolds-Young-Laplace model and compared to the experimental data. Numerically calculated net force curves are in excellent agreement with experimental data from the literature when charge-dipole attraction is included, while they deviate in its absence. In addition, the water droplet and thin oil film profiles in the presence and absence of charge-dipole attraction were calculated and compared. This research indicates that charge-dipole attraction can adequately explain the mysterious force observed in some studies, which demonstrates its unexplored potential to capture the physical properties and dynamic behavior of water droplets in organic phases with useful implications to unravel unidentified interactions between emulsion droplets in different industries.

Unraveling the Role of Charge Patterning in the Micellar Structure of Sequence-Defined Amphiphilic Peptoid Oligomers by Molecular Dynamics Simulations.

Electrostatic interactions play a significant role in regulating biological systems and have received increasing attention due to their usefulness in designing advanced stimulus-responsive materials. Polypeptoids are highly tunable N-substituted peptidomimetic polymers that lack backbone hydrogen bonding and chirality. Therefore, polypeptoids are suitable systems to study the effect of noncovalent interactions of substituents without complications of backbone intramolecular and intermolecular hydrogen bonding. In this study, all-atom molecular dynamics (MD) simulations were performed on micelles formed by a series of sequence-defined ionic polypeptoid block copolymers consisting of a hydrophobic segment and a hydrophilic segment in an aqueous solution. By combining the results from MD simulations and experimental small-angle neutron scattering data, further insights were gained into the internal structure of the formed polypeptoid micelles, which is not always directly accessible from experiments. In addition, information was gained into the physics of the noncovalent interactions responsible for the self-assembly of weakly charged polypeptoids in an aqueous solution. While the aggregation number is governed by electrostatic repulsion of the negatively charged carboxylate (COO–) substituents on the polypeptoid chain within the micelle, MD simulations indicate that the position of the charge on singly charged chains mediates the shape of the micelle through the charge–dipole interactions between the COO– substituent and the surrounding water. Therefore, the polypeptoid micelles formed from the single-charged series offer the possibility for tailorable micelle shapes. In contrast, the polypeptoid micelles formed from the triple-charged series are characterized by more pronounced electrostatic repulsion that competes with more significant charge–sodium interactions, making it difficult to predict the shape of the micelles. This work has helped further develop design principles for the shape and structure of self-assembled micelles by controlling the position of charged moieties on the backbone of polypeptoid block copolymers.