Photonic crystals in biology - NanoTR-VI

PPPPPoster Session, Thursday, June 17Theme F686 - N11231Binary Memory Cells on the Base of Stimuli-Sensitive Macromolecules122UIbragim SuleimenovUP P*, Grigoriy MunP Pand Ellina MunPPAIPET – Almaty Institute of Power Engineering and Telecommunications, Baitursynova 126, Almaty 050013, Kazakhstan2PChemical faculty of Kazakh National University, Karasai Batyra 95, 050012 Almaty, KazakhstanAbstract-It is shown that macromolecules of thermosensitive polymer with hysteresis properties may be synthesized. It was shown theoreticallyand experimentally that systems with information recording density comparable to molecular can be produced on the base of such polymers.At present time, an active search of systems providing fordata recording at molecular and submolecular level takesplace. Search in this direction is stimulated by well-knownfact: the most compact data recording is realized in biologicalsystems.In the present work a base for elaboration of data recordingsystems using synthetic macromolecules were laid. It is shownthat in solutions of stimuli-responsive polymers hysteresisphenomena take place. The dependence of solution’s opticaldensity on temperature obtained under the solution heatingdiffers significantly from the analogous curve obtained underits cooling. This is the basis for realization of digital units.Poly-N-isopropylacrylamid (PNIPAM) aqueous solution(MM= 135 000 with concentrations 0,2 weight % wasanalyzed). The dependence of solution’s optical density underheating and cooling in quasistationary regime with thermostating was registered. The example of results obtained isshown at Figure 1. It can be seen that curves obtained differconsiderably from each other, besides, it is seen that there is atemperature span which two different states of system can berealized in.10,80,60,40,2D, rel. units2031 32 33 34 35 36 37Figure1. Temperature dependence of optical density of PNIPAMaqueous solution from the temperature, obtained at increase (1) anddecrease (2) of temperature.One of these states can be considered as logical zero, anotherone-as logical one; conversion between them can beconsidered as data recording. One should underline, that it isnot necessary for this conversion from one state to another toaffect system as a whole. This conclusion was demonstratedby the example of cross-linked analogue of explored polymer,i.e. gel (poly)N-isopropylacrylamide. It is known that suchnetwork is thermosensitive, i.e. its degree of swelling in waterand water solutions depends significantly on temperature.Firstly, it was experimentally shown that hysteresisphenomena, i.e. difference between dependences of degree ofswelling on temperature obtained under the heating andcooling of sample, takes place for gel of specified type too.Secondly, it was found that conversion from one state toanother can pass locally under sample’s weak heating andfollowing temperature adjustment up to the value TR01T,0PCR(Figure2). Net parts corresponding to different states, whichcan be put in accordance to logical zero and one, can existunder the same thermodynamic variables (temperature,pressure).Therefore, hydrogel sample showing local hysteresisphenomena can be considered as a medium suitable for datarecording. Dimensions of individual memory cell dependsignificantly on the network’s elastic properties and are quitebig. However, they can be decreased at the expense ofconversion to individual macromolecules.Figure 2. Temperature corresponds to two logical variablesTheory that confirm this conclusion for individualmacromolecules is developed in the work. This theory showsthat hysteresis phenomena of molecules of thermosensitivepolymer are caused by formation of intramolecular micelles.The formation mechanism is completely analogous to thatpassing in solutions of surfactants. The fact of existence ofhysteresis phenomena itself allows to conclude that under thecertain values of thermodynamic variables the fragments,which form or not form micelles, can co-exist in the samechain.Correlation of this conclusion with behavior of hydrogelmicroscopic sample shows that data recording can be realizedwith high density. Dimensions of individual digital unit aredetermined by dimensions of macromolecular chain fragmentscapable to form micelle. At least, under the condition of weakinteraction between individual macromolecules in solutionseach of them can quite possess the properties of binarymemory cell.We show, that complexes formed by such thermosensitivemacromolecules on the surface of solid body may be used asan alternative data recording system. Possibility of using ofsuch complexes for creation of adapters capable to be aconnecting-link between classic solid-state circuit componentand systems of information processing on the quasibiologicalbasis is discussed.* Correspondign author: Esenych@yandex.ru6th Nanoscience and Nanotechnology Conference, zmir, 2010 683