pH Responsive Polymeric Brush Nanostructures: Preparation and Characterization by Scanning Probe Oxidation and Surface Initiated Polymerization

Abstract

pH-responsive PHEMA-based polymeric nanostructures were grown in a controlled manner by ATRP-based surface-initiated polymerization. Initiator nanopatterns were obtained on silicon wafers covered with OTS resists made by AFM scanning probe oxidation lithography. AFM images confirmed isolated grafting of stimuli-responsive hedge and dot brush structures exhibiting dimensions corresponding to a few tens of chains.

Polymer Nanostructures Made by Scanning Probe Lithography: Recent Progress in Material Applications

“…Polymer brushes Poly( N -isopropylacrylamide) (PNIPAM), PMMA, etc., [ 48 ] PS, PNIPAM and PNBA [ 51 c , 61 ] nanoshaving, nanoscratching physical: mechanical scratching of the surface layer [ 48 ] or brush fi lm [ 51c , 61 ] 100 nm 1D cantilever array photopolymerization of coumarinderivative thiols [ 56 ] [ 49 ] polymer brushes by ROMP, [ 55 ] PAA, PNIPAM, POEGMA etc., [ 62 ] PAA [ 63 ] AFM electrochemical oxidation chemical: electrochemical oxidation of the substrate, [ 49 , 55 ] brush fi lm [ 62 ] or initiators [ 63 ] 40 nm, [ 49 , 62 ] ≈ 200 nm [ 63 ] single tip the many examples, DPN and its derivatives are the most frequently reported tools for parallel patterning. The parallelization route has rendered SPL as potentially competitive with other serial nanolithographic tools, such as industrial EBL.…”

“…[ 47 ] Functional polymer brush nanostructures fabricated by means of SPL have shown a wide range of applications. For example, responsive nanopatterned surfaces have been fabricated with either solvent-sensitive [ 48 ] or pH-sensitive [ 49 ] brushes. Not only can the reversible switching of the chain conformation be studied at the nanometer level, but also surface actuation can be triggered to hide/unveil functional surfaces.…”

Controlled Surface Initiated Polymerization of N‐Isopropylacrylamide from Polycaprolactone Substrates for Regulating Cell Attachment and Detachment

“…[15][16][17][18][19] Surface-initiated ATRP was used with great success to obtain designed surfaces exhibiting coatings with thicknesses in the nanoscale with targeted and controlled properties. [1][2][3][4] Gold and silicon were most often employed as substrates for polymerization [3][4][20][21][22][23][24][25][26][27][28] , although tissue culture polystyrene (TCPS) [29][30][31] or titanium [32][33][34][35][36] were also investigated as substrates for biomedical applications. In the specific case of polymer-based scaffolds for tissue engineering, the use of biocompatible polymer substrates, such as poly(ε-caprolactone) (PCL) or other polyester based polymers, is desirable.…”

"Chameleon" macromolecules: synthesis, structures and applications of stimulus responsive polymers

“…The presence of contact area heterogeneities could also explain why a broader distribution was obtained for the LD sample. In order to study the dynamics of the switching of PNIPAM grafts from the swollen to the collapsed state, the adherence (pull-off force) 90 between the sample surface and the AFM colloidal probe was monitored by recording force curves at constant time intervals. The change in the polymer chain conformation and swelling state causes a change in adherence between the polymer grafts and the AFM probe, as reported earlier.…”

“…79 Nanopatterned polymer grafts with defined features become especially interesting when the pattern dimensions are close to the length of the grafted macromolecules. [80][81][82] AFM-based techniques, such as nanoscratching, 83,84 dip-pen nanolithography (DPN) [85][86][87] and scanning probe oxidation (SPO) [88][89][90] offer versatile patterning techniques across the length scales. Advantages of AFM based methods for the nano-fabrication include high resolution, the ability to generate features with nearly arbitrary geometries, and a precise position control.…”