Large Molar Mass Research Articles

TFE Terpolymers: Once Promising - Are There Still Perspectives in the 21st Century: Synthesis, Characterization, and Properties-Part I.

Polytetrafluoroethylene (PTFE) exhibits outstanding properties such as high-temperature stability, low surface tension, and chemical resistance against most solvents, strong acids, and bases. However, these traits make it challenging to subject PTFE to standard polymer processing procedures, such as thermoforming and hot incremental forming. While polymer processing at temperatures above the melting point of PTFE is already demanding, the typically large molar mass of PTFE results in extremely high melt viscosities, complicating the processing of PTFE. Also, PTFE tends to decompose at temperatures close to its melting point. Therefore, fluoropolymers obtained by copolymerizing tetrafluoroethylene (TFE) with various co-monomers are studied as alternatives to PTFE (e.g., fluorinated ethylene-propylene (FEP)), combining its advantages with better processability. TFE terpolymers have emerged as desirable PTFE alternatives. This review provides an overview of the synthesis with various comonomers and microstructural analysis of PTFE terpolymers and the relationships between the microstructures of TFE terpolymers and their properties.

Proton-Conducting Membranes from Polyphenylenes Containing Armstrong's Acid.

This study demonstrates the use of 1,5-naphthalenedisulfonic acid as a suitable building block for the efficient and economic preparation of alternating sulfonated polyphenylenes with high ion-exchange capacity (IEC) via Suzuki polycondensation. Key to large molar masses is the use of an all-meta-terphenyl comonomer instead of m-phenyl, the latter giving low molar masses and brittle materials. A protection/deprotection strategy for base-stable neopentyl sulfonates is successfully implemented to improve the solubility and molar mass of the polymers. Solution-based deprotection of polyphenylene neopentyl sulfonates at 150 °C in dimethylacetamide eliminates isopentylene quantitatively, resulting in membranes with high IEC (2.93 mequiv/g) and high proton conductivity (σ = 138 mS/cm). Water solubility of these copolymers with high IEC requires thermal cross-linking to prevent their dissolution under operating conditions. By balancing the temperature and time of the cross-linking process, water uptake can be restricted to 50 wt %, retaining an IEC of 2.33 mequiv/g and a conductivity of 85 mS/cm. Chemical stability is addressed by treatment of the membranes under Fenton's conditions and by considering barrier heights for desulfonation using density functional theory (DFT) calculations. The DFT results suggest that 1,5-disulfonated naphthalenes are at least as stable as sulfonated polyphenylenes against desulfonation.

Comment on “Lewis acid-surfactant complex catalysed polymerisation in aqueous dispersed media: cationic or radical polymerisation?” by A. Destephen, L. Lezama and N. Ballard, Polym. Chem., 2020, 11, 5757

Cationic polymerization catalysed by LASC occurs when radical production is inhibited and at low temperature. Large molar mass distributions obtained in this process call for a mechanism involving preferential coordination of dienic or styrenic monomers by the catalyst.

Mutual and Thermal Diffusivities in Binary Mixtures of n-Hexane or 1-Hexanol with Krypton, R143a, or Sulfur Hexafluoride by Using Dynamic Light Scattering and Molecular Dynamics Simulations

This work reports Fick diffusion coefficients D11 in the saturated liquid phase(s) of binary mixtures of nonpolar n-hexane (n-C6H14) or polar 1-hexanol (1-C6H14O) with dissolved krypton (Kr), 1,1,1-trifluoroethane (R143a), or sulfur hexafluoride (SF6). Investigations were performed at temperatures T of 303, 323, and 348 K and gas mole fractions up to 0.999. The comparison between Kr and R143a, both having nearly the same molar mass, allows identification of the impact of molecular structure and polarity of the dissolved gas on D11. The investigation of SF6 provides information about the influence of a centrosymmetric molecule with a large molar mass on D11. D11 is experimentally determined by dynamic light scattering (DLS) and predicted by equilibrium molecular dynamics (EMD) simulations by the independent calculation of the Maxwell–Stefan diffusivity and the thermodynamic factor Γ11 in macroscopic thermodynamic equilibrium at or close to saturation conditions. Thermal diffusivity data obtained simultaneously with D11 by DLS are reported as well. The behavior of the experimentally determined D11 as a function of composition and that obtained from EMD simulations show generally good agreement. Distinct structural changes of the saturated liquid phase are reflected by the change of Γ11 which extends for the present study between 0.16 and 1.3. While for mixtures of 1-C6H14O + Kr, D11 as a function of composition is nearly constant at a given T, all other mixtures show a distinct composition-dependent behavior. For mixtures of 1-C6H14O + R143a and 1-C6H14O + SF6, a strong slowing down of D11 was observed and related to approaching a liquid–liquid miscibility gap. For all systems, the behavior of D11 as a function of composition is interpreted with reference to the fluid structure accessible by EMD.

Compatibilization of Polymer Blends by Ionic Bonding

Chemically dissimilar polymers are rarely miscible due to a specific entropy of mixing that scales as 1/N, where N is the degree of polymerization. As a consequence, the compatibilization of immiscible polymer blends presents a major challenge to plastics recycling efforts. We demonstrate that when the chain ends of two highly immiscible polymers are functionalized with reacting acid and base groups, ionic junctions form in situ by proton transfer, leading to the stabilization of interfaces and the suppression of macroscopic phase separation. Due to the dynamic nature of proton transfer, the microstructure can be tuned via ionic bond energy (h) and segregation strength (χN). In this work, a library of ionically end-functionalized polystyrene (PS) and polydimethylsiloxane (PDMS) is used to demonstrate the importance of end-group acidity/basicity and molecular weight on compatibilization. Well-ordered lamellae result from blending polymers with strong acid and base units, while less ordered, more swollen microphases occur in systems with weak acid and base end groups or larger molar mass. Heating the ionic blends results in reverse proton transfer and destruction of the close-contact ion pairs. As a result, domains are swollen with the resulting unbonded homopolymers, which in sufficient amounts, leads to macrophase separation. Moreover, external salt ions screen the electrostatic attractions and disturb ionic compatibilization. The self-consistent field theory (SCFT) of this system reveals that the ionic interactions can be tuned to create a broad range of morphologies, from microphases to macrophases.

Influence of de-structured starch on fine-stranded polymeric and coarse-stranded particulate whey protein gels

This study investigated the phase stability of liquid mixtures and composite gels properties of de-structured waxy potato starch (DWPS) and whey protein isolate (WPI). The DWPS are physically-modified starches treated at 120, 140 and 150 °C for 30 min under constant shear. The composite gels (13% w/w WPI and 4% w/w DWPS) characteristics at pH 7 and pH 5 were evaluated based on their mechanical properties, microstructure, and water-immersion stability. At pH 7, the addition of DWPS did not result in any phase separation. Synergistic gel hardness of WPI was obtained with incorporation of 140 °C DWPS likely due to the enhanced density of a very fine-stranded gel network. The ability of the gel to retain its shape when immersed in water for 40 h was prominent for composite gels containing either gelatinised starch (control) or DWPS samples. In contrast, pure WPI gels and composite gels containing maltodextrin appeared fluid-like and disintegrated gels, respectively. At pH 5, the addition of gelatinised starch or DWPS weakened the particulate protein gels, likely due to phase separation and interrupted protein network with starch polymers acting as an inactive filler. A logarithmically decline in gel hardness was noted as the molar mass of DWPS increased. The coarse porous structure of particulate gels exhibited poor water-holding capacity, low water absorption, and high degree of starch leaching. However, the higher molar mass DWPS polymers enhanced the water-holding capacity of the gels and reduced their own diffusivity from the gel network. • 140 °C DWPS synergistically enhanced the polymeric gel network of WPI. • WPI + DWPS polymeric gels had good shape retention after 40 h water immersion. • Particulate WPI gel strength decreased with increasing molar mass of DWPS samples. • DWPS in particulate WPI gel existed as an inactive filler. • Large molar mass DWPS could disrupt the connectivity of particulate WPI gels.

Synthesis and Spectroscopic Analyses of New Polycarbonates Based on Bisphenol A-Free Components.

This paper discusses a new synthesis of bisphenol A-free polycarbonates based on four aliphatic–aromatic systems. In the first stage, different types of monomers (with/without sulfur) derived from diphenylmethane were synthesized. Then, new polycarbonates were prepared in the reactions with diphenyl carbonate (DPC) by transesterification and polycondensation reactions. Three different catalysts (zinc acetate, 4-(dimethylamino)pyridine and benzyltriethylammonium chloride) were tested. The structures of the compounds were confirmed by Nuclear Molecular Resonance spectroscopy (NMR) in each stage. The chemical structures of the obtained polycarbonates were verified by means of Attenuated Total Reflectance Fourier Transform infrared spectroscopy (ATR–FTIR). The presence of a carbonyl group in the infrared spectrum confirmed polycarbonate formation. Thermal studies by differential scanning calorimetry (DSC) were carried out to determine the melting temperatures of the monomers. A gel permeation chromatography analysis (GPC) of the polycarbonates was performed in order to investigate their molar masses. Thermal analysis proved the purity of the obtained monomers; the curves showed a characteristic signal of melting. The obtained polycarbonates were characterized as having high resistance to organic solvents, including tetrahydrofuran. The GPC analysis proved their relatively large molar masses and their low dispersity.

A nonchlorinated solvent-processed polymer semiconductor for high-performance ambipolar transistors.

Ambipolar polymer semiconductors are potentially serviceable for logic circuits, light-emitting field-effect transistors (LFETs) and polymer solar cells (PSCs). Although several high-performance ambipolar polymers have been developed, their optoelectronic devices are generally processed from toxic chlorinated solvents. To achieve the commercial applications of organic FETs (OFETs), the polymers should be processed from nonchlorinated solvents, instead of chlorinated solvents. However, most conjugated polymers show poor solubility in nonchlorinated solvents. It is of great importance to develop ambipolar polymers that can be processed from nonchlorinated solvents. Here, we develop a nonchlorinated solvent processed polymer named poly[7-fluoro-N, N′-di(4-decyltetradecyl)-7′-azaisoindigo-6′,6″-(thieno[3,2-b]thiophene-2,5-diyl)-7‴-fluoro-N″, N‴-di(4-decyltetradecyl)-7″-azaisoindigo-6,6‴-([2,2″-bithiophene]-5,5″-diyl)] (PITTI-BT) by designing a monomer with a large molar mass. The polymer displays good solubility in p-xylene (PX). Well-aligned films of PITTI-BT are achieved by an off-center spin-coating (SC) method. Based on the high-quality films, the OFETs fabricated from PX solution achieve record ambipolar performance with hole and electron mobilities of 3.06 and 2.81 cm2 V−1 s−1, respectively. The combination of nonchlorinated solvents and good alignment process offers an effective and eco-friendly approach to obtain high-performance ambipolar transistors.

Effects of Soft Matter on G-Protein-Coupled Receptor Activation

G protein-coupled receptors (GPCRs) constitute both the largest class of medicinal targets and the largest family of human membrane proteins. Current three-dimensional structures have shown the existence of many water molecules immersed inside GPCRs. However, the functional role of these water molecules has remained uncertain. Our previous work has shown that water modulates the activation of visual rhodopsin, a prototypical GPCR [1]. Here we expanded our approach to further investigate how the conformational energetics of GPCR activation are modulated by water using a series of osmolytes that included polyethylene glycols (PEGs), dextrans, polyvinylpyrrolidones (PVPs), and their monomers. We hypothesized that osmotic pressure affects the thermodynamic stability of conformational substates of photoactivated rhodopsin. Accordingly, we changed the osmotic stress on rhodopsin using different concentrations of various polymer solutes. Shifting of the metarhodopsin equilibrium due to the osmotic pressure was probed using UV-visible spectroscopy. The larger osmolytes (e.g., PEG 1500-6000) promote the inactive metarhodopsin-I (MI) state, while the small organic osmolytes such as smaller molar mass PEGs, their monomers, and small sugars increase the active metarhodopsin-II (MII) fraction. These size effects are a result of the degree of penetration of osmolytes into the protein core of rhodopsin. Small polymers penetrate the protein core and favor the open MII state of rhodopsin, while the large polymers behave like ideal osmolytes and dehydrate rhodopsin. Most interestingly, PEGs and dextrans with extremely large molar masses deviated in their trends from other large polymers (PEGs), which we attribute to a combined result of crowding and penetration effects. The results provide us with new insights into the interplay between osmotic stress, penetration, and crowding effects. Our findings further the understanding of the vital role of water in the GPCR activation mechanisms. [1] U. Chawla et al. (2020) Angew.Chem.Int.Ed. doi:10.1002/anie.202003342.

A branched structure provides kraft lignins a denser morphology and a high molar mass for a given hydrodynamic radius

AbstractSize exclusion chromatography with multi-angle laser light-scattering detectors was applied for acetylated softwood and hardwood kraft lignins (Ac-SKL and Ac-HKL) and 8-O-4′ type of linear polymeric lignin model (Ac-M-8O4′) to compare their swelling behaviors. The plot of molar mass (MM) vs. retention time for Ac-M-8O4′ was similar to that of polystyrene, which revealed that Ac-M-8O4′ exhibited swelling behavior that was similar to that of polystyrene. However, the MM values of both Ac-KLs were larger than those of polystyrene standards at any retention time. This difference indicated that both Ac-KLs had a more compact structure than those of polystyrene and Ac-M-8O4′. One hypothesis is that the larger MM of both Ac-KLs stems from their branched structures. To verify this hypothesis, the frequency of 5-5′ interunit linkage in lignin samples was determined by1H NMR after nitrobenzene oxidation. A linear relationship between MM and 5-5′ abundance was observed in the high MM region.

IMPREGNATED FIBROUS CHEMOSORBENTS OF ACID GASES FOR RESPIRATORY PURPOSE

The present review is dedicated to the analysis of scientific works carried out in Physico- Chemical Institute of Environment and Human Protection (Odessa, Ukrainie) and directed to the development of import-substituting sorption-filtering materials for respiratory purposes – impregnated fibrous chemisorbents (IFCS) of acid gases, which are manufactured using standard equipment, as well as affordable and inexpensive chemical reagents and carriers of domestic origin. The process of chemisorption of sulphur dioxide by hexamethylenetetramine (HMTA) modified nonwoven fibrous material resulted acid-catalyzed hydrolysis of HMTA to form aminomethanesulfonic acid and toxic formaldehyde. The IFCS with HMTA carried was recommended to use for air purification only from SiF4, HF, HCl and Cl2. Chemisorption of sulphur dioxide by fibrous materials impregnated by ethanolamines (monoethanolamine, diethanomamine, triethanomamine and N-methylethanolamine) and polyethylenepolyamine (PEPA) occurs only in the presence of “free” water with formation of “onium” sulphites, hydrosulphites and pyrosulphites. IFCS-PEPA (dynamic activity is 1,38 mmol(SO2)/g) are not inferior to the protective characteristics of IFCS with Na2CO3, HMTA, ethanolamines and the best foreign ionexchange fibrous chemisorbents brand VION and FIBAN (dynamic activity is 0,263 ÷0,422 mmol(SO2)/g) under conditions of respirators actual use (jAGM = 60 ÷ 90 %, TAGM = 297 K, VAGM = 2,0 sm/s, СSO2 = 20 ÷ 1000 mg/g3, QPEPA = 3,45 mmol/g). It is recommended to use the condensation products of primary alkylamines with formaldehyde (with large molar masses than the bases), complex compounds of amines with 3d-metals (Ni(II) and Cu(II)), salts of amine with aminoacids (glycine) and polybasic acids (orthophosphoric acid (pKa1 = 2,12) and citric acid (pKa1 = 3,13)) for manufacturing of IFCS of acid gases The IFCS with indication of dynamic absorptive capacity “wearing” (IVKS-I) was developed.

Polymerization of alkyl methacrylate nanoemulsions made by the phase inversion temperature method

The polymerization of several alkyl methacrylates in nanoemulsions made by the phase inversion temperature method is presented here. The temperature versus surfactant concentration fish-like phase diagrams for a fixed mixture of alkyl methacrylate/squalane (SQ) of 95/5 w/w, Brij 56 and water were elaborated. Reaction rates were extremely fast (ca. 100% conversion in less than 3 min), and only two reaction rate intervals were observed, which is typical of nanoemulsion polymerization. It suggests that chain transfer to monomer is the main termination mechanism. The addition of squalane inhibits monomer diffusion from small droplets to larger ones and prevents the diffusion of monomer from non-reacting droplets to reacting ones, which guarantees that each monomer droplet acted as a nanoreactor. Polymer particles have similar size than the original nanoemulsion droplets indicating that the nanodroplets act as templates for the formation of the polymer nanoparticles. Reaction rates, as well as kinetics and nanoparticle characterizations by quasielastic light scattering (QLS), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), are reported. Spheroidal nanoparticles with similar sizes and narrow distribution were observed by TEM for poly(ethyl methacrylate), poly(butyl methacrylate), and poly(hexyl methacrylate). The large molar masses and the narrow molar mass distributions were obtained by gel permeation chromatography.

Bipyridinium and Imidazolium Ionic Liquids for Nanomaterials Synthesis: pH Effect, Phase Transfer Behavior, and Protein Extraction

We demonstrate the potential use of 1,1′-bis(2-(cyclohexyloxy)-2-oxoethyl)-[4,4′-bipyridin]-1,1′-diium bromide (BP) and 1-ethyl-3-methylimidazolium chloride (EMI) ionic liquids (ILs) in in situ synthesis of gold nanoparticles (Au NPs) without using any external reducing or stabilizing agents. Both ILs produced nearly monodisperse NPs of 4–8 nm which were present in the form of self-assembled states. BP coated NPs formed self-assembled sheets and easily transferred to the organic phase by employing the water insoluble IL as a phase transfer agent. The efficiency of the phase transfer process was related to the extent of aggregation as well as functional groups. Both IL coated NPs were further used to extract the proteins from the complex biological mixtures. EMI coated NPs extracted proteins of large molar masses whereas BP coated NPs were good for the extraction of low molecular mass proteins. This disparity was controlled by the substituted functional groups of ILs. Bulky cyclohexyloxy functional groups ...

Solution conformation and flexibility of capsular polysaccharides from Neisseria meningitidis and glycoconjugates with the tetanus toxoid protein.

The structural integrity of meningococcal native, micro-fluidized and activated capsular polysaccharides and their glycoconjugates – in the form most relevant to their potential use as vaccines (dilute solution) - have been investigated with respect to their homogeneity, conformation and flexibility. Sedimentation velocity analysis showed that the polysaccharide size distributions were generally bimodal with some evidence for higher molar mass forms at higher concentration. Weight average molar masses Mw where lower for activated polysaccharides. Conjugation with tetanus toxoid protein however greatly increased the molar mass and polydispersity of the final conjugates. Glycoconjugates had an approximately unimodal log-normal but broad and large molar mass profiles, confirmed by sedimentation equilibrium “SEDFIT MSTAR” analysis. Conformation analysis using HYDFIT (which globally combines sedimentation and viscosity data), “Conformation Zoning” and Wales-van Holde approaches showed a high degree of flexibility – at least as great as the unconjugated polysaccharides, and very different from the tetanus toxoid (TT) protein used for the conjugation. As with the recently published finding for Hib-TT complexes, it is the carbohydrate component that dictates the solution behaviour of these glycoconjugates, although the lower intrinsic viscosities suggest some degree of compaction of the carbohydrate chains around the protein.

The pH-responsive behaviour of poly(acrylic acid) in aqueous solution is dependent on molar mass.

Fluorescence spectroscopy on a series of aqueous solutions of poly(acrylic acid) containing a luminescent label showed that polymers with molar mass, Mn < 16.5 kDa did not exhibit a pH responsive conformational change, which is typical of higher molar mass poly(acrylic acid). Below this molar mass, polymers remained in an extended conformation, regardless of pH. Above this molar mass, a pH-dependent conformational change was observed. Diffusion-ordered nuclear magnetic resonance spectroscopy confirmed that low molar mass polymers did not undergo a conformational transition, although large molar mass polymers did exhibit pH-dependent diffusion.

Formation of polyelectrolyte complexes with diethylaminoethyl dextran: Charge ratio and molar mass effect

The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains.

ATRP-template dispersion polymerization of methacrylic Acid/PVP

ATRP-template dispersion polymerization of methacrylic acid (MAA) on the template of polyvinyl pyrrolidone (PVP K-30) was carried out in the aqueous solution by using methyl 2-bromopropionate (MBP)/CuCl/2,2′-bipyridine (bpy) as the initiation system. The scanning electron microscopy (SEM), dynamic light scattering (DLS) and gel permeation chromatography (GPC) were employed for evaluating the results of polymerization. As a result, the minimonomer droplets formed due to the H-bond interaction of PVP-MAA. The stability of droplets was dependent on pH and the concentrations of both PVP and MAA. When pH 4.5, the droplets were not observable by DLS. In order to prepare the stable latex, the concentration of PVP should be lower than 9 wt%, whilst the concentration of MAA should be lower than 5.5 wt%. The optimum condition was pH 2.4, PVP 4.76 wt% and MAA 5 wt%, by which the stable latex of ca. 50 nm nanoparticles of PMAA/PVP was prepared by ATRP polymerization and simultaneously the molar mass of PVP was duplicated by PMAA according to GPC diagrams. In contrast, by using AIBN, KPS and KPS-Na2SO3 redox initiation system, the coagulum accompanying with the larger molar mass of PMAA was obtained, irrespective of pH and concentrations of PVP and MAA.

Organic Preparations with Molar Amounts of Volatile Malodorous Thiols

Thiols are indispensable for the preparation of many organic sulfur compounds. Their strong smell and use for gas leakage perception render it almost impossible to work with them without arousing public attention. Molar amounts of the very odoriferous thiol 2-methyl-2-propanethiol (t-butylthiol) are needed, for example, for the large-scale synthesis of two useful synthetic building blocks, 1,2,4,5-tetrakis(t-butylthio)benzene and tetramethylbenzo-2,2,6,6-[1,2-d;4,5-d']bis[1,3]dithiol. We investigated an array of alternatives to circumvent the problem: (1) alternative thiols (primary, long-chain, tertiary thiols of larger molar mass); (2) exhaust cleaning methods (adsorption, oxidation, conversion to a salt); and (3) thermal exhaust treatment. Only combustion of the fumehood exhaust with domestic gas at 900 °C in a regenerative thermal oxidation unit was able to completely prevent the thiol smell from escaping. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

Thermodynamic Stability of Structure H Hydrates Based on the Molecular Properties of Large Guest Molecules

This paper report analyses of thermodynamic stability of structure-H clathrate hydrates formed with methane and large guest molecules in terms of their gas phase molecular sizes and molar masses for the selection of a large guest molecule providing better hydrate stability. We investigated the correlation among the gas phase molecular sizes, the molar masses of large molecule guest substances, and the equilibrium pressures. The results suggest that there exists a molecular-size value for the best stability. Also, at a given molecule size, better stability may be available when the large molecule guest substance has a larger molar mass.

On the impacts of phytoplankton-derived organic matter on the properties of the primary marine aerosol – Part 2: Composition, hygroscopicity and cloud condensation activity

Abstract. The effect of nanogel colloidal and dissolved organic matter &lt;0.2 μm, secreted by marine biota, on the hygroscopic growth and droplet activation behaviour of the primary marine aerosol was studied. Seawater proxies were prepared by the combination of artificial seawater devoid of marine organics and natural seawater enriched in organic exudate released by laboratory-grown phytoplankton cultures, as described in a companion paper. The primary aerosol was produced by bubble bursting, using a plunging multijet system as an aerosol generator. The aerosol generated from seawater proxies enriched with marine exudate presented organic volume fractions on the order of 8–37%, as derived by applying a simple mixing rule. The hygroscopic growth and cloud condensation nuclei (CCN) activity of the marine organics-enriched particles where 9–17% and 5–24% lower, respectively, than those of the aerosol produced from artificial seawater devoid of exudate. Experiments in a companion paper indicated that the cloud nuclei formation could be enhanced in diatom bloom areas because of the increase in the primary particle production induced by marine organics. The experiments in the present study, however, indicate that the impacts of such an enhancement would be counteracted by the reduction in the CCN activity of the primary particles enriched in marine organics. The extent of the effect of the biogenic matter on the particle behaviour was dependent on the seawater organic concentration and type of algal exudate. Aerosol produced from seawater proxies containing diatomaceous exudate presented higher hydrophobicity and lower CCN activity than those enriched with nanoplankton exudate. The organic fraction of the particles was found to correlate with the seawater organic concentration, without observing saturation of the particle organic mass fraction even for unrealistically high organic matter concentration in seawater. These findings are indicative that discrepancies on the composition of the primary aerosol between different studies could partly be explained by the difference in the nature and concentration of the organic matter in the source seawater employed. Consistently across the experiments, theoretical analysis based on the Köhler model predicted a reduction in the primary marine aerosol CCN activity upon the incorporation of marine organics into the particle composition. This effect is consequence of the replacement of small inorganic sea salt molecules by large molar mass organic molecules, together with a moderate suppression of the surface tension at the point of activation of 5–0.5%, which leads to a dominance of the reduction in the dissolved solute in the Raoult term.