Wormlike micelles are elongated flexible self-assembly structures formed by the aggregation of amphiphiles. Above a threshold concentration, they entangle into a dynamic network, reminiscent of polymer solutions, and display remarkable visco-elastic properties, which have been exploited in numerous industrial and technological fields. Relating the microstructure of these intricate structures with their bulk properties is still an ongoing quest. In this review, we present a classification of wormlike micelles, with a focus on novel systems and applications. We describe the current state of understanding of their linear rheology and give a detailed account of recent progress in small-angle neutron scattering, a particularly powerful technique to elucidate their microstructure on a wide range of length-scales.

Wormlike micelles: where do we stand? Recent developments, linear rheology and scattering techniques

Objective: The objective of this study was to analyze the correlation between degrees of clinical improvement and microscopic changes detected using confocal microscopy at the temperature gradients reached in patients treated for skin laxity with a phase-controlled, multisource radiofrequency system. Design and setting: Patients with skin laxity in the abdominal area were treated in six sessions with radiofrequency (the first 4 sessions were held at 2-week intervals and the 2 remaining sessions at 3-week intervals). Patients attended monitoring at 6, 9, and 12 months. Participants: 33 patients (all women). Measurements: The authors recorded the following: variations in weight, measurements of the contour of the treated area and control area, evaluation of clinical improvement by the clinician and by the patient, images taken using an infrared camera, temperature (before, immediately after, and 20 minutes after the procedure), and confocal microscopy images (before treatment and at 6, 9, and 12 months). The degree of clinical improvement was contrasted by two external observers (clinicians). The procedure was performed using a new phase-controlled, multipolar radiofrequency system. Results: The results reveal a greater degree of clinical improvement in patients with surface temperature increases greater than 11.5oC at the end of the procedure and remaining greater than 4.5oC 20 minutes later. These changes induced by radiofrequency were contrasted with the structural improvements observed at the dermal-epidermal junction using confocal microscopy. Changes are more intense and are statistically correlated with patients who show a greater degree of improvement and have higher temperature gradients at the end of the procedure and 20 minutes later. Conclusion: Monitoring and the use of parameters to evaluate end-point values in skin quality treatment by multisource, phased-controlled radiofrequency can help optimize aesthetic outcome. (J Clin Aesthet Dermatol. 2011;4(1):28–35.)

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Multisource, Phase-controlled Radiofrequency for Treatment of Skin Laxity: Correlation Between Clinical and In-vivo Confocal Microscopy Results and Real-Time Thermal Changes

Complex Fluids of Poly(oxyethylene) Monoalkyl Ether Nonionic Surfactants

The present invention provides improved methods and apparatus for skin treatment and tissue remodeling. The apparatus includes an array of needles that penetrate the skin and serve as electrodes to deliver radio frequency current or other electrical or optical energy into the tissue being treated, causing thermal damage in controlled patterns. The damaged regions promote beneficial results such as uniform skin tightening by stimulation of wound healing and collagen growth.

Method and apparatus for dermatological treatment and tissue reshaping

Wormlike micelles in mixed surfactant solutions

Background: Regardless of diet and exercise, genetics plays an important part in creating puckering skin or dimples, which are difficult to hide at any age. The demand for a nonsurgical, noninvasive treatment of cellulite has inspired some manufacturers to invest in a new age of sophisticated devices and treatment therapies to repair the skin and improve contours. Although many of these new choices have demonstrated a smoothing effect (following a multitude of treatments), the objective documentation has in most cases been limited to biopsies, circumference measurements, and photographic evidence. Hypothesis: We believe that the application of noninvasive high-energy radiofrequency (RF) to the skin of the thigh and buttocks heats the subcutaneous adipose tissue, causing collagen fibers to contract. The resulting impact to the subcutaneous tissue and collagen is expected to improve the skin's external architecture. Given that the subcutaneous tissue and adipose tissue are difficult to evaluate through histological methods, this investigation seeks to demonstrate the changes that occur when applying 2 treatments of high-energy RF on the subcutaneous tissue of thighs and buttocks utilizing real-time ultrasound image scanning. Materials and Methods: Twenty-six healthy female patients (ages 18 to 50) with visible bilateral cellulite (grade 1 to 3) on either the buttocks and/or thighs received 2 treatment sessions (15 days apart) of unipolar RF using the Accent RF System (Alma Lasers Inc). The system utilizes a unipolar RF applicator that is electrically cooled to aid in patient comfort during the treatment. Appropriate energy was set and the treatment was delivered in 3 passes of 30 seconds each. Evaluation of the thickness of the subcutaneous tissue on buttocks and thighs took place before the first treatment, second treatment, and 15 days following the second treatment with a with real-time scanning image ultrasound (Philips Medical Systems). Clinical improvement was objectively evaluated through comparative pre- and post-treatment measurements of the distance between the stratum corneum to the Camper's fascia and from the stratum corneum to the muscle. The study also evaluated the structure and changes of the collagen (thickening and realignment of septae) resulting from 2 treatments of RF. Photography was used to document contour and superficial changes. Results: From the measurements of the distance between the stratum comeum to the Camper's fascia and from the stratum corneum to the muscle we were able to demonstrate that 68% of the patients presented a contraction of the volume of approximately 20%. Conclusions: Based on the demonstrated results with real-time ultrasound scanning, we have observed that 2 RF treatments on the subcutaneous tissue of the buttocks and thighs provide a volumetric contraction effect in the majority of patients. This validates the primary hypothesis of our protocol and establishes that the RF energy works on the connective tissue of the subcutaneous adipose tissue. This effect should be the same on any other body part.

Effect of controlled volumetric tissue heating with radiofrequency on cellulite and the subcutaneous tissue of the buttocks and thighs.

Phase diagrams of water; sodium dodecyl sulfate (SDS); and a new foam booster, alkanoyl-N-methylethanolamide (C8, NMEA-8; C12, NMEA-12; C16, NMEA-16), were constructed at 25 °C. NMEA is hardly solu...

Phase and Rheological Behavior of Surfactant/Novel Alkanolamide/Water Systems

The phase behavior and structures of liquid crystals in aqueous solution of Pluronic copolymers (P85; (PEO) 26 (PPO) 40 (PEO) 26 , P105; (PEO) 37 (PPO) 58 (PEO) 37 ) mixed with nonionic surfactants (C 12 EO 5 , C 18:1 EO 5 ) were investigated. In a binary water/P85 system, the sequence of self-assemblies is similar to that of the aqueous P105 system, and aqueous micellar solution, micellar cubic, hexagonal, and lamellar phases are successively formed. P85 forms a single lamellar liquid crystal (L α ) with C 12 EO 5 in water at high concentration, whereas two L α phases coexist in the water/P105/C 12 EO 5 system. Two coexisting lamellar phases become identical at a critical point upon replacing P105 with P85. We calculated the average cross-sectional area, a S , at the hydrophobic interface using SAXS data. The partial molecular areas of copolymer, a S P, and surfactant, a S S, were also evaluated from as values obtained at different compositions of the copolymer-surfactant mixture. It was found that a S P decreases and a S S slightly increases in the copolymer L α phase with increasing the surfactant mixing fraction in the copolymer-surfactant mixture.

Miscibility of Block Copolymers and Surfactants in Lamellar Liquid Crystals

Phase diagrams and microstructure of aggregates in mixed ionic surfactant/foam booster systems.

Resumen es: La representacion clasica de movimiento de la extremidad superior es muy adecuada para describir movimientos individuales que se realizan en planos, pero...

http://www.redalyc.org/pdf/1210/Resumenes/Resumen_121014219003_1.pdf

Carlos F. Rodriguez

Papers

Effect of controlled volumetric tissue heating with radiofrequency on cellulite and the subcutaneous tissue of the buttocks and thighs.

Phase and Rheological Behavior of Surfactant/Novel Alkanolamide/Water Systems

Miscibility of Block Copolymers and Surfactants in Lamellar Liquid Crystals

Phase diagrams and microstructure of aggregates in mixed ionic surfactant/foam booster systems.

Revista de Ingeniería