Andrei Sergeevich Bureiko

Current applications of foams formed from mixed surfactant–polymer solutions

Foams cannot be generated without the use of special foaming agents, as pure liquids do not foam. The most common foaming agents are surfactants, however often for foam stability one active agent is not enough, it is necessary to add other component to increase foam lifetime. Foams on everyday use are mostly made from mixture of different components. Properly chosen combinations of two active ingredients lead to a faster foam formation and increased foam stability. During the last decade polymers (mainly polyelectrolytes and proteins) have become frequently used additives to foaming solutions. Mixtures of surfactants and polymers often demonstrate different foaming properties in comparison to surfactant only or polymer only solutions. The nature of surfactant-polymer interactions is complicated and prediction of resulting foaming properties of such formulations is not straightforward. Properties and foaming of surfactant-polymer mixtures are discussed as well as current applications of foams and foaming agents as foams are widely used in cosmetics, pharmaceutics, medicine and the food industry.

Colloidal Structure and Physical Properties of Gel Networks Containing Anionic Surfactant and Fatty Alcohol Mixture

We investigated the mechanical properties, thermal behavior, physical state, and colloidal structure of a model gel network formulated with various ratios of sodium dodecyl sulfate polyacrylamide (SDS) and cetyl/stearyl fatty alcohol (FA) mixture in constant amounts of water (89%). The metastable gel, formed by slowly cooling stirred samples from temperatures above the chain melting temperature (Tm) of the long chain FA, has a lamellar structure with a periodic inter bilayer spacing of approximately 30 nm. The bilayers remain homogeneous with SDS being immobilized in the FA matrix upon chain freezing. The chain length mismatch leads to an increased structural disorder among the alkyl chains upon SDS incorporation among the FA. As a result, the elastic modulus decreased with increasing SDS content. Conclusions were based on a large number of experiments involving differential scanning calorimetry, rheology, 1H NMR spectroscopy, and small angle x-ray scattering. Results from this work have uncovered the physical nature of these networks and gave insight into the role of anionic surfactants on the assembly, physical state, and mechanical properties of gel networks.

Polymer and foams in hair care products [Abstract]

Hair care products are expected to wet well human hair, even when the hair is hydrophobic. Thus, wetting properties of human hair are very important, as they influence consumer satisfaction with the products. Wettability of a hair tress is an important characteristic. The wetting behavior of polymer solutions on hair is less studied than surfactant solutions. The wetting of hair tresses by aqueous solutions of commercially available polymers AculynTM 22 (A22) and AculynTM 33 (A33) has been investigated. Both experimental studies and numerical simulations of behavior of polymer solutions and foams on tresses of human hair has been investigated including drainage of foams produced from solutions of those polymers and interaction of foams with hair stresses are presented. Both A22 and A33 solutions demonstrate well pronounced shear thinning behavior. Initial contact angle of the A22 and A33 solutions on undamaged hair tresses is about 100 o. The A22 droplets remained on the hair tress after spreading for at least half an hour. However, a fast penetration of the A33 droplet inside the hair tresses was observed when advancing contact angle in the course of spreading reaches a critical value of about (60 o). Pure solutions of A22 and A33 have higher initial contact angle and longer penetration time on hair tresses compared with the solutions containing i-propanol or sodium dodecyl sulphate. The results demonstrate that wetting kinetics of the polymer solution on hair tresses drastically different depending on the formulation and can vary from a rapid imbibition to a spreading only.One of the major disease manifestations of systemic lupus erythematosus (SLE) is lupus nephritis (LN), and the underlying mechanisms are not yet understood. Epstein-Barr virus (EBV) reactivation was associated with the induction of SLE, with EBV-encoded latent membrane protein1 (LMP1) plays a vital role in this process. Although it was reported that LN was associated with LMP1, most of these results are from patients with ages differed greatly (range, 10-56 years). Given the increased prevalence of EBV infection in young patients, we focused on the association of LN and LMP1 expression in the renal tissues of young patients (range, 6-16 years) in this study. We found that the positive rate of LMP1 in the renal tissues was significantly higher in patients with LN compared with control (P<0.001), which is consistent with the previous reports. The positive rates of LMP1 were similar between the patients of initial onset and relapse, and there was no detectable difference between the patients with and without concurrent infection (P>0.05). However, we reported for the first time about the positive correlation of LMP1 with classification of LN. The proportion of young patients positive for anti‑Sm antibody was significantly higher in the LMP1 positive group compared with the LMP1 negative control (P>0.05). These results indicate that EBV infection in the renal of young patients may lead to the increased severity of LN, and the expression of anti-Sm is likely contributed to this process.Human hair is a nanocomposite biological fiber. Maintaining the health, feel, shine, color, softness, and overall aesthetics of the hair is highly desired. Hair care products such as shampoos and conditioners, along with damaging processes such as chemical dyeing and permanent wave treatments, affect the maintenance and grooming process and are important to study because they alter many hair properties. Nanoscale characterization of the cellular structure, mechanical properties, and morphological, frictional, and adhesive properties (tribological properties) of hair are essential to evaluate and develop better cosmetic products, and to advance the understanding of biological and cosmetic science. The tensile response of hair is of considerable interest. Another property of interest is the surface charge of hair, which has a significant effect on manageability, feel, and appearance. For this reason, controlling charge buildup to improve these factors is an important issue in the commercial hair care industry. The atomic/friction force microscope (AFM/FFM) and nanoindenter have recently become important tools for studying the micro/nanoscale properties of human hair. In this talk, we present a comprehensive review of the cellular structural, nanomechanical, and nanotribological properties of various hair and skin as a function of ethnicity, damage, conditioning treatment, and various environments1-2. Various cellular structures of human hair and fine sublamellar structures of the cuticle are identified and studied. Nanomechanical properties such as hardness, elastic modulus, creep and scratch resistance are discussed. Nanotribological properties such as roughness, friction, and adhesion are presented, as well as investigations of conditioner distribution, thickness, and binding interactions.