Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)最新文献

{"title":"Controlled Light-Driven Levitation of Macroscopic Plates","authors":"Mohsen Azadi, G. Popov, Zhipeng Lu, Andy G. Eskenazi, A. Bang, M. Campbell, Howard H. Hu, I. Bargatin","doi":"10.3390/micromachines2021-09569","DOIUrl":"https://doi.org/10.3390/micromachines2021-09569","url":null,"abstract":"Photophoretic or light-driven levitation has been studied extensively in the context of the motion of illuminated micron-sized particles, such as dust grains in the atmosphere under sunlight [1,2], and in relation to Crooks radiometers [3]. When heated by incident light, a micron-sized particle experiences a temperature gradient that in turn results in uneven gas-surface interactions and a net propulsive force [4]. Though thoroughly investigated for micron-sized particles, this phenomenon has rarely been studied to controllably levitate macroscopic objects. \u0000We report light-driven levitation of 0.5-um thick mylar samples that have been modified by depositing a 300-nm-thick layer of carbon nanotubes (CNTs) on a single side. The CNT layer serves three key purposes: 1) It acts as a lightweight light absorber, absorbing ~ 90% of the incident light and elevating the temperature of the sample. 2) It increases the structural rigidity of the mylar film, allowing cm-scale discs with submicron thicknesses to hold their shape. 3) It creates a structured porous surface that traps impinging gas molecules, which results in an accommodation coefficient difference between the top and bottom surfaces for gas-surface interactions. Air molecules that rebound from the CNT-coated side have on average higher velocities than those departing from the opposing uncoated mylar surface. We show that the net force thus created can be used to levitate the mylar films. Moreover, we will demonstrate our ability to manipulate a light field in order to control the flight of levitating samples for extended periods of time. \u0000 \u0000References: \u0000 \u0000Jovanovic, O. Photophoresis—Light induced motion of particles suspended in gas. Journal of quantitative spectroscopy & radiative transfer 110, 889–901, (2009) \u0000Horvath, Photophoresis – a forgotten force ??, KONA powder and particle journal, 31, 181–199 (2014) \u0000Ketsdever, N. Gimelshein, S. Gimelshein, and N. Selden, “Radiometric phenomena: From the 19th to the 21st century”, Vacuum 86, 1644-1662 (2012). \u0000Loesche, G. Wurm, T. Jankowski, M. Kuepper, Photophoresis on particles hotter/colder than the ambient gas in the free molecular flow. J. Aerosol Sci, 97, 22–33 (2016)","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128062935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nanotribological investigation of the poly(3-hydroxybutyrate) films manufactured from the storage polyesters produced by Halomonas elongata DSM 2581","authors":"M. Pustan, C. Bîrleanu, A. Cristea, H. Banciu","doi":"10.3390/MICROMACHINES2021-09564","DOIUrl":"https://doi.org/10.3390/MICROMACHINES2021-09564","url":null,"abstract":"Poly(3-hydroxybutyrate) (PHB) is a natural and biodegradable storage polyester, produced by numerous bacteria, which is considered a potential substituent for conventional plastics in the packaging industry. The improvement of the PHB material lifetime often involves the mechanical and tribological characterization which can be accurately performed on thin films. In this study, we aimed at the evaluation of the tribological properties, like adhesion force, friction coefficient and wear resistance, of different polyester films fabricated via the solvent casting method [1]. Three polyester films were designed in this study, each containing 1% w/v constituents as follows: a PHBh film prepared out of the PHB extracted from the extremely halotolerant bacteria Halomonas elongata DSM2581T, a PHBc film fabricated using a commercially available PHB and a PHBVc film generated using the commercial poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The spectroscopy-in-point of AFM was used for adhesion force measurement based on multiple tests performed in a matrix and the AFM lateral operating mode was applied for friction analysis under a controlled normal load. The fabricated PHBh film presented a thickness between 5 µm -7 µm, a lower adhesion force (14 nN) as well as a smaller friction coefficient (0.15) compared to the PHBc and PHBVc. The tribological investigations of PHBh film revealed a biodegradable material with low roughness as well as small adhesion and friction forces. Further optimization can be performed for the improvement of the PHBh film by copolymerization with other polymers, polyesters and reinforcers, thus generating a feasible material with advanced tribo-mechanical features. \u0000References \u0000[1] Cristea A, Pustan M, Birleanu C, Dudescu C, Floare CG, Tripon AM, Banciu HL. (2021) Mechanical evaluation of solvent casted poly(3-hydroxybutyrate) films derived from the storage polyesters produced by Halomonas elongata DSM 2581T. J Polym Environ, Submitted: ID: JOOE-S-21-00260.","PeriodicalId":137788,"journal":{"name":"Proceedings of Micromachines 2021 — 1st International Conference on Micromachines and Applications (ICMA2021)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127725795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}