Ice Growth Rate Research Articles

Treatment of compressed leachate from refuse transfer stations by freeze-melt method

A small amount of leachate with complex composition will be produced during the compressing of municipal solid waste in refuse transfer stations. In this study, the freeze-melt method, a green and efficient wastewater treatment technology, was used to treat the compressed leachate. The effects of freezing temperature, freezing duration, and ice melting method on the removal rates of contaminants were investigated. The results showed that the freeze-melt method was not selective for the removal of chemical oxygen demand (COD), total organic carbon (TOC), ammonia-nitrogen (NH3-N) and total phosphorus (TP). The removal rate of contaminants was positively correlated with freezing temperature and negatively correlated with freezing duration, and the slower the growth rate of ice, the higher the purity of ice. When the compressed leachate was frozen at −15 °C for 42 h, the removal rates of COD, TOC, NH3-N and TP were 60.00%, 58.40%, 56.89% and 55.34%, respectively. Contaminants trapped in ice were removed during the melting process, especially in the early stages of melting. The divided melting method was more beneficial than the natural melting method in removing contaminants during the initial stage of melting, which contributes to the reduction of produced water losses. This study provides a new idea for the treatment of small amounts of highly concentrated leachate generated by compression facilities distributed in various corners of the city.

Sea ice and snow characteristics from year-long transects at the MOSAiC Central Observatory

Repeated transects have become the backbone of spatially distributed ice and snow thickness measurements crucial for understanding of ice mass balance. Here we detail the transects at the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) 2019–2020, which represent the first such measurements collected across an entire season. Compared with similar historical transects, the snow at MOSAiC was thin (mean depths of approximately 0.1–0.3 m), while the sea ice was relatively thick first-year ice (FYI) and second-year ice (SYI). SYI was of two distinct types: relatively thin level ice formed from surfaces with extensive melt pond cover, and relatively thick deformed ice. On level SYI, spatial signatures of refrozen melt ponds remained detectable in January. At the beginning of winter the thinnest ice also had the thinnest snow, with winter growth rates of thin ice (0.33 m month−1 for FYI, 0.24 m month−1 for previously ponded SYI) exceeding that of thick ice (0.2 m month−1). By January, FYI already had a greater modal ice thickness (1.1 m) than previously ponded SYI (0.9 m). By February, modal thickness of all SYI and FYI became indistinguishable at about 1.4 m. The largest modal thicknesses were measured in May at 1.7 m. Transects included deformed ice, where largest volumes of snow accumulated by April. The remaining snow on level ice exhibited typical spatial heterogeneity in the form of snow dunes. Spatial correlation length scales for snow and sea ice ranged from 20 to 40 m or 60 to 90 m, depending on the sampling direction, which suggests that the known anisotropy of snow dunes also manifests in spatial patterns in sea ice thickness. The diverse snow and ice thickness data obtained from the MOSAiC transects represent an invaluable resource for model and remote sensing product development.

Tracking changes in the fjord environment over a winter season using ice bulk salinity and δ18O

Ice that forms in the fjords of northern Norway often undergoes temperature fluctuations, rising above and below freezing, throughout winter and experiences variable conditions at the ice-ocean interface due to changes in freshwater runoff from surrounding land. Conditions at the interface can be difficult to track throughout the season without consistent measurement, resultantly limiting understanding of how freshwater runoff from land may impact a fjord throughout winter. Ice samples gathered from fjords, however, offer a unique opportunity to examine the connection between bulk ice properties like salinity and δ18O and environmental conditions including growth rate and the composition of water at the interface. Using relationships from the literature, a method was developed to invert bulk ice salinity and δ18O simultaneously to determine the history of growth rate and interface water composition of ice samples gathered in March 2018 from six fjords located in northern Norway. Quantitative results depend on knowledge of salinity and δ18O of both the seawater and freshwater leading into the fjord. It was found that five of the six investigated sites had ice grown from a brackish layer with 0 to 40% seawater content, while one site had ice grown from water with 50 to 90% seawater content. The brine volume fraction of the ice from four out of the six fjords was partly or entirely below 5% which is too low to allow for efficient brine transport. It is additionally shown that at ice temperatures between −2 and 0 °C, ice grown from water having a composition of up to 30% seawater at the ice ocean interface will fall below the 5% brine volume fraction, depending on growth rate. Through use of this method, an improved understanding was obtained of fluctuations in the composition of water at the ice-ocean interface in a sub-arctic coastal environment and, when ice growth rate is considered, the substantial influence on ice bulk properties.

Application of a simple model for ice growth to the Lake St. Moritz, Switzerland

AbstractWe present a Simple Lake Ice Model to calculate the growth rate of lake ice in a cold and relatively dry climate. The focus is on Lake St. Moritz, Switzerland, which has an area of 0.78 km2 and is about 45 m deep. In winter the lake is extensively used for recreational purposes, including horse racing with thousands of spectators. Safety on the ice cover is essential, and there is a great need to have a simple tool with which the growth rate of the ice layer can be calculated for given meteorological conditions. The approach is based on a simple formulation of the upper temperature of the ice layer, which depends on air temperature and snow cover. Input data are the date on which the lake freezes over, daily mean air temperatures and snow depth. For the winter 2021/22 calculated ice growth compares well with ice thickness measurements. We demonstrate that grooming of the snow has a significant positive effect on the ice thickening rate. We also evaluate the sensitivity of the simulated ice thickness to increasing mean temperature.

Rotational dynamics of water associated with interfacial dielectric oscillation and its role in crystal growth of ice.

The rotational dynamics of water near the ice/water interface and its relation with the crystal growth of ice are investigated by using molecular dynamics simulations. We find that the dipole-moment profiles of water adjacent to interfaces display an oscillation behavior, which is in contrast to the monotonic decay near the free surface for water films. This dielectric oscillation phenomenon is associated with the strong response to hard solid/water interface. It significantly suppresses the dielectric relaxation and slows down the rotational diffusion near the interface compared to bulk water. We propose that the rotational diffusion determines the active degree of growth sites on interfaces, and its slowdown due to the interfacial dielectric oscillation contributes to reducing the growth rate of ice. With this idea, we predict the crystal growth rate of ice based on the modified Wilson-Frenkel model involving rotational dynamics. The theoretical result agrees well with the simulation.

Janus regulation of ice growth by hyperbranched polyglycerols generating dynamic hydrogen bonding

In this study, a new phenomenon describing the Janus effect on ice growth by hyperbranched polyglycerols, which can align the surrounding water molecules, has been identified. Even with an identical polyglycerol, we not only induced to inhibit ice growth and recrystallization, but also to promote the growth rate of ice that is more than twice that of pure water. By investigating the polymer architecture and population, we found that the stark difference in the generation of quasi-structured H2O molecules at the ice/water interface played a crucial role in the outcome of these opposite effects. Inhibition activity was induced when polymers at nearly fixed loci formed steady hydrogen bonding with the ice surface. However, the formation-and-dissociation dynamics of the interfacial hydrogen bonds, originating from and maintained by migrating polymers, resulted in an enhanced quasi-liquid layer that facilitated ice growth. Such ice growth activity is a unique property unseen in natural antifreeze proteins or their mimetic materials.

Snow redistribution onto young sea ice: Observations and implications for climate models

Vertical heat conduction through young ice is a major source of wintertime sea ice growth in the Arctic. However, field observations indicate that young ice preferentially accumulates wind-blown snow, resulting in greater snow thickness on young ice than would be expected from precipitation alone, and hence greater snow thickness on young ice than climate models represent. As snow has a low thermal conductivity, this additional snow thickness due to redistribution will reduce the actual heat conduction. We present new observations from the Multidisciplinary drifting Observatory for the Study of Arctic Climate Expedition which show that young ice rapidly accumulates a snow thickness of 2.5–8 cm, when wind-blown snow is available from the nearby mature ice. By applying a simple redistribution scheme and heat flux model to simulated conditions from the Community Earth System Model 2.0, we suggest that neglecting this snow redistribution onto young ice could result in the potential overestimation of conductive heat flux—and hence ice growth rates—by 3–8% on average in the Arctic in the winter in the absence of climate feedbacks. The impacts of snow redistribution are highest in the springtime and in coastal regions.

Remotely Monitored Buoys for Observing the Growth and Development of Sea Ice In Situ

Abstract This paper describes a remotely monitored buoy that, when deployed in open water prior to freeze up, permits scientists to monitor not only temperature with depth, and hence freeze up and sea ice thickness, but also the progression of sea ice development—e.g., the extent of cover at a given depth as it grows (solid fraction), the brine volume of the ice, and the salinity of the water just below, which is driven by brine expulsion. Microstructure and In situ Salinity and Temperature (MIST) buoys use sensor “ladders” that, in our prototypes, extend to 88 cm below the surface. We collected hourly measurements of surface air temperature and water temperature and electrical impedance every 3 cm to track the seasonal progression of sea ice growth in Elson Lagoon (Utqiaġvik, Alaska) over the 2017/18 ice growth season. The MIST buoy has the potential to collect detailed sea ice microstructural information over time and help scientists monitor all parts of the growth/melt cycle, including not only the freezing process but the effects of meteorological changes, changing snow cover, the interaction of meltwater, and drainage. Significance Statement There is a need to better understand how an increasing influx of freshwater, one part of a changing Arctic climate, will affect the development of sea ice. Current instruments can provide information on the growth rate, extent, and thickness of sea ice, but not direct observations of the structure of the ice during freeze up, something that is tied to salinity and local air and water temperature. A first deployment in Elson Lagoon in Utqiaġvik, Alaska, showed promising results; we observed fluctuations in ice temperatures in response to brief warmings in air temperature that resulted in changes in the conductivity, liquid fraction, and brine volume fraction within the ice.

Spatiotemporal Analysis and Modeling of Sea Ice Growth Rate in Nella Fjord, Antarctica: Based on Observations During the 36th Chinese National Antarctic Research Expedition in 2020

Obtaining field sea ice data is crucial for the validation and improvement of satellite data and numerical models. During the 36th Chinese National Antarctic Research Expedition, seven field observations covering the whole area were conducted in Nella Fjord, and large amounts of in situ sea ice and snow thickness data were acquired. Then, the influences of snow cover, topography, and air temperature on the sea ice growth rate were examined. Based on the relationship between the sea ice growth rate and air temperature, an empirical model of sea ice thickness was developed. The results show that sea ice started to freeze in early March, and the peak growth rate was reached in mid-June, with a mean growth rate of 0.62 cm/d. Between mid-June and mid-October, the mean growth rate was 0.36–0.4 cm/d; between mid-October and mid-November, the mean growth rate decreased to 0.15 cm/d. After mid-November, ice growth stopped, and the ice thickness decreased. The growth rate and thickness of sea ice near the shore were generally greater than those closer to the center of the fjord, with differences of 0.25 cm/d in mean growth rate and 7.16 cm in mean thickness. Because of the large exchanges of heat between the atmosphere and the ocean, the sea ice thickness increased rapidly during the early stage of freeze-up. When the air temperature was between -12 and −15°C, the ice growth rate was between 0.36 and 0.4 cm/d. However, when the ice thickness reached 0.5 m, the sea ice growth rate became less sensitive to air temperature. In addition, we found that the proposed model has high simulation accuracy for the growth rate of sea ice. Based on the model, we estimated that the growth rates become zero at an air temperature of approximately −4°C. Our study highlights the inverse relationship between the sea ice growth rate and the snow thickness and the fact that the sea ice thickness is mainly affected by air temperature.

Solute inclusion during progressive freeze concentration: A state diagram approach

We propose a conceptual model for progressive freeze concentration, which predicts solute loss through inclusion in the ice based on the system's phase behaviour as illustrated in a state diagram. We compare the outcomes of the model for sodium chloride, sucrose, and bovine serum albumin (BSA). For ice growth rates in the order 10−2 μm/s there was no solute inclusion for sodium chloride or sucrose, but above this range, local super-cooling gives rise to a freezing zone. In this freezing zone ice and solution co-exist and the resulting uneven advancement of the ice causes inclusions. The model predicts that for macromolecular solutions such as BSA, no inclusion will take place through the proposed mechanism.

A floating remote observation system (FROS) for full seasonal lake ice evolution studies

A floating remote observation system (FROS) was designed to investigate the full seasonal evolution of lake ice. FROS operates effectively in open water and ice. It can automatically measure meteorological data, such as the air temperature and solar radiation, as well as ice/snow data, including ice thickness and snow depth. These observations help to fill the current knowledge gap of lake ice observations during the early freezing and late melting periods because of the limited bearing capacity of ice cover. A mid-latitude lake was selected for field experiments to verify the effectiveness of FROS, where the duration of the survey was 101 days, of which 97 were during an ice-covered period. The results reveal that the lake ice went through a fast freezing period, equilibrium period, and a melting period, with a maximum ice thickness of 35.5 cm. The ice melting rate was 1.7 cm/day, which was approximately double the ice growth rate of 0.7 cm/day during the fast freezing period. FROS was able to record the complete evolution of lake ice and of different meteorological elements, with good stability in both open water and frozen conditions, and can accommodate wind speeds up to 6.4 m/s. Meanwhile, FROS has good versatility, and other measurement instruments such as chlorophyll and dissolved oxygen sensors, longwave radiometers, and conductivity sensors can be added to it. The application of FROS will be important for calculations of the thermal balance of snow and ice, and studies of the annual and seasonal evolution of ecological characteristics in frozen lakes.

The study on the impinging freezing of the supercooled droplet containing the atmosphere aerosol

The aerosols have significant effect on the nucleation of supercooled droplet in the atmosphere. In this paper, the impinging freezing and static isothermal freezing experiments of the supercooled droplet were conducted to investigate the effect of potassium feldspar (K-feldspar), as the representative of aerosols, on the impinging freezing process. The results show that the impingement has more effect than K-feldspar on the freezing of supercooled droplet on the cold substrate. However, the K-feldspar can increase the impinging freezing probability of supercooled droplet further, and the higher the concentration of K-feldspar, the greater the influence. The freezing probability model in the static freezing and impinging freezing was established. Significantly, these freezing probability curves of K-feldspar suspension are exponential function and linearly proportional to the concentration approximately.However,the K-feldspar has little effect on the nucleation time during the impinging freezing. Moreover, by comparing the impinging freezing process, not only the nucleation but also the ice growth could be affected by the K-feldspar, leading to different final freezing morphology. The horizontal growth rate of ice could be increased by 3–10% because of K-feldspar, and the higher the temperature, the more the increase. Finally, according to the nucleation and ice growth process, the spreading ratio model was established and could predict the spreading ratio on various substrates. Spreading ratio of K-feldspar suspension is higher than pure droplet.

Effects of the atmospheric forcing resolution on simulated sea ice and polynyas off Adélie Land, East Antarctica

Coastal polynyas of the Southern Ocean play a central role in the ventilation of the deep ocean and affect the stability of ice shelves. It appears crucial to incorporate them into climate models, but it is unclear how to adequately simulate them. In particular, there is no consensus on the atmospheric forcing resolution needed to appropriately model the sea ice in coastal Antarctica. A high resolution might be required to represent the local winds such as katabatic winds which are key drivers of coastal polynyas. To fill in this gap, we have tested the sensitivity of sea ice and air-sea-ice interactions to the resolution of the atmospheric forcing in a high-resolution ocean–sea ice model. A set of regional atmospheric simulations at horizontal resolutions of 20, 10, and 5 km are performed with an atmospheric regional model and used to force three ocean–sea ice simulations in the Adélie Land sector, East Antarctica. Due to the better representation of topography with a refined grid, the offshore component of coastal winds becomes stronger at increased resolution. The wind intensification is particularly strong down valleys channelizing the katabatic flow, with increase in wind speed ranging between 1 and 3 m/s. Under a higher resolution forcing, polynyas open more frequently and are wider. This fosters the growth rate of sea ice in polynyas, while landfast ice and pack ice are weakly affected. In polynyas, the production of sea ice is increased by up to 30% at 5 km resolution compared to 20 km resolution. Polynyas downstream of the katabatic wind pathway are more affected than the ones driven by easterly winds, highlighting the importance of the local wind conditions. Brine rejection associated with these higher sea ice production rates affects the salinity budget of the ocean and enhances both the volume and density of the dense Shelf Water produced off Adélie Land. These results underpin the need to better account for local coastal winds and polynyas in ocean and climate models.

The combined use of progressive and block freeze concentration in lactose‐free milk: Effect of process parameters and influence on the content of carbohydrates and proteins

AbstractThis work focuses on the study of the concentration of lactose‐free milk using a combination of progressive freezing concentration (PFC) with block freezing concentration (BFC). First, we investigated the PFC of skim lactose‐free milk applying response surface methodology. To analyze the influence of three factors (stirring rate, coolant temperature, and assay time) on the response variables (concentrate yield, efficiency of the process, concentration index, and average ice growth rate), a central composite design was used previously. It was found that all factors had a significate influence on the responses. Then, once the optimized condition for this step was chosen (time of 58 min, coolant temperature of −5°C, and mechanical stirring of 1,035 rpm), the ice obtained from it was subjected to a new freeze concentration cycle using the BFC assisted by vacuum. In the concentrated fraction of this cycle, protein and carbohydrate contents were equals to 6.7 g 100 g−1and 10.24 g 100 g−1, respectively. The results suggest that in PFC carbohydrates accumulate more in the concentrated phase, while in BFC it is the protein that has the greatest tendency to pass into the concentrated liquid. In this approach, we believe that it is possible to combine the two techniques (PFC + vacuum‐assisted BFC) to obtain concentrates, and that they can be used for the development of innovative lactose‐free dairy products.Practical ApplicationsThe use of concentration processes can facilitate the customization of milk products rich in proteins to meet specific requirements on nutritional and functional properties, for instance in bakery products, formulated food, ice‐cream, beverages, energy drinks, and others. Moreover, since most changes occur in an aqueous environment, the removal of some part of milk water results in its preservation. Within the concentration processes, the freeze concentration emerges swiftly thanks to its inherent features, involving low‐temperature processing and selective nature of the water removal step. Because of the low temperatures used in freeze concentration, this technology is gaining in popularity as an alternative technique to the standard concentration techniques currently used in dairy processing. It offers the most enhanced functional and sensorial qualities of concentrated milk because it decreases the quality deviation by minimizing the heat abuse on sensitive milk components, such as proteins, water‐soluble vitamins, and aromatics.

Freeze desalination of drops of saline solutions

This study investigates freeze desalination achieved through partial freezing of drops of saline solutions. Firstly, a parametric study is performed to determine the ice recovery (%) and salinity reduction (%) for drops of NaCl solutions as a function of drop size, NaCl concentration and freezing temperature. It was shown that desalination can be achieved in millimetric drops at freezing temperatures pertinent to their partial freezing state. Overall, greater supercooling degrees were required for higher salt concentrations, leading to a higher ice recovery (%) in smaller drops for a given salt concentration. The salinity reduction (%), however, reduced linearly as the ice recovery (%) increased, with drops of greater salt concentrations showing the least salinity reduction. The higher ice growth rate experienced by such drops is believed to be responsible for the observed lower salinity reduction (%).A map of freezing state is developed for drops of 1, 3.5 and 6 wt% NaCl solution. The map identifies the drop's state of freezing in terms of unfrozen, partially frozen, and fully frozen state. This map can be employed to identify the temperature range required for achieving partial freezing of saline drops, the pre-requisite for drop-based freeze desalination processes.

How the growth of ice depends on the fluid dynamics underneath

Convective flows coupled with solidification or melting in water bodies play a major role in shaping geophysical landscapes. Particularly in relation to the global climate warming scenario, it is essential to be able to accurately quantify how water-body environments dynamically interplay with ice formation or melting process. Previous studies have revealed the complex nature of the icing process, but have often ignored one of the most remarkable particularities of water, its density anomaly, and the induced stratification layers interacting and coupling in a complex way in the presence of turbulence. By combining experiments, numerical simulations, and theoretical modeling, we investigate solidification of freshwater, properly considering phase transition, water density anomaly, and real physical properties of ice and water phases, which we show to be essential for correctly predicting the different qualitative and quantitative behaviors. We identify, with increasing thermal driving, four distinct flow-dynamics regimes, where different levels of coupling among ice front and stably and unstably stratified water layers occur. Despite the complex interaction between the ice front and fluid motions, remarkably, the average ice thickness and growth rate can be well captured with the theoretical model. It is revealed that the thermal driving has major effects on the temporal evolution of the global icing process, which can vary from a few days to a few hours in the current parameter regime. Our model can be applied to general situations where the icing dynamics occur under different thermal and geometrical conditions.

A Synthesis of Observations and Models to Assess the Time Series of Sea Ice Mass Balance in the Beaufort Sea

AbstractOver the past four decades, there has been a substantial thinning of the summer sea ice cover in the Beaufort Sea. Variations in sea ice mass balance reflect these changes and give insight to the environmental forcings which caused them. In this work, the time series results from eight Lagrangian mass balance sites that operated in the Beaufort Sea over the years 1997–2015 are analyzed. Direct measurements from the sites are combined with estimates of ice/ocean heat input to examine the roll of solar heating on ice loss, growth, and melt rates. Comparisons between ice and snow conditions and mass balance event timing, for example, surface and bottom melt onset, melt peak, and melt end, are also made. From the late 1990s to the present, a general increase in bottom melting and solar heat input to the upper ocean was observed. All sites showed a net loss of ice (ranging from 29 to 271 cm), and all but one site saw the majority of this loss from bottom melting. Bottom melt onset occurred within a relatively narrow 13‐day window between 1 and 13 June at all sites. The amount of observed bottom melt was also related to the heat deposited in the ocean available for melting, underscoring the increasingly important role of ocean thermodynamics in determining sea ice mass balance.

Skill and Potential Economic Value of Forecasts of Ice Accretion on Wind Turbines

AbstractIn this paper, a verification study of the skill and potential economic value of forecasts of ice accretion on wind turbines is presented. The phase of active ice formation on turbine blades has been associated with the strongest wind power production losses in cold climates; however, skillful icing forecasts could permit taking protective measures using anti-icing systems. Coarse- and high-resolution forecasts for the range up to day 3 from global (IFS and GFS) and limited-area (WRF) models are coupled to the Makkonen icing model. Surface and upper-air observations and icing measurements at turbine hub height at two wind farms in central Europe are used for model verification over two winters. Two case studies contrasting a correct and an incorrect forecast highlight the difficulty of correctly predicting individual icing events. A meaningful assessment of model skill is possible only after bias correction of icing-related parameters and selection of model-dependent optimal thresholds for ice growth rate. The skill of bias-corrected forecasts of freezing and humid conditions is virtually identical for all models. Hourly forecasts of active ice accretion generally show limited skill; however, results strongly suggest the superiority of high-resolution WRF forecasts relative to other model variants. Predictions of the occurrence of icing within a period of 6 h are found to have substantially better accuracy. Probabilistic forecasts of icing that are based on gridpoint neighborhood ensembles show slightly higher potential economic value than forecasts that are based on individual gridpoint values, in particular at low cost-loss ratios, that is, when anti-icing measures are comparatively inexpensive.

Mass and Heat Balance of a Lake Ice Cover in the Central Asian Arid Climate Zone

To improve the understanding of the seasonal evolution of the mass and heat budget of ice-covered lakes in the cold and arid climate zone, in-situ observations were collected during two winters (2016–2017 and 2017–2018) in Lake Wuliangsuhai, Inner Mongolia, China. The mean snow thickness was 5.2 and 1.6 cm in these winters, due to low winter precipitation. The mean ice thickness was 50.9 and 36.1 cm, and the ice growth rate was 3.6 and 2.1 mm day−1 at the lower boundary of ice. Analyses of mass and heat balance data from two winters revealed that the surface heat budget was governed by solar radiation and terrestrial radiation. The net heat flux loss of the ice was 9–22 W m−2, affected by the snow and ice thickness. Compared to boreal lakes, Lake Wuliangsuhai received more solar radiation and heat flux from the water. The ice temperature had a strong diurnal variation, which was produced by the diurnal cycles of solar radiation, and air and water temperatures. These results expand our knowledge of the evolution of mass and heat balance in temperate lakes of mid-latitude arid areas.

Ice Recrystallization Inhibition Activity of Protein Mimetic Peptoids

Natural antifreeze proteins are known for their excellent control of ice formation and growth, while synthetic molecules seldom have the similar effects. Here we report a series of protein mimetic peptoids with different side chains exhibiting significant ice recrystallization inhibition activity, and their structure–property relationships are also studied. The presence of peptoid can clearly slow down ice growth and decrease ice crystal grain size, but shows no thermal hysteresis, which make peptoids great antifreeze agent candidates in cryopreservation. Peptoids with methyl, ethyl and amino groups on side chains can modulate ice crystal shape, while peptoids bearing hydroxyl and ethyl groups decrease ice growth rate the most. All peptoids can reduce ice crystal grain size and the one with hydroxyl groups give the smallest grain size. This study reveals peptoid structure effects on ice growth and points to the design rules for biomimetic antifreeze agents.