Full article ">Figure 1
<p>The molecular structure of some well-known molecular tweezers synthesized by different research groups. Redrawn from references [<a href="#B7-surfaces-07-00049" class="html-bibr">7</a>,<a href="#B13-surfaces-07-00049" class="html-bibr">13</a>,<a href="#B14-surfaces-07-00049" class="html-bibr">14</a>,<a href="#B17-surfaces-07-00049" class="html-bibr">17</a>,<a href="#B19-surfaces-07-00049" class="html-bibr">19</a>,<a href="#B20-surfaces-07-00049" class="html-bibr">20</a>], respectively.</p> Full article ">Figure 2
<p>Chemical structure of water-soluble Zimmerman molecular tweezers on the dextran scaffold. Redrawn from reference [<a href="#B47-surfaces-07-00049" class="html-bibr">47</a>].</p> Full article ">Figure 3
<p>Maitra’s molecular tweezers immobilized on the polystyrene. The image illustrates the attachment of the tweezers to a polystyrene bead. Redrawn from reference [<a href="#B19-surfaces-07-00049" class="html-bibr">19</a>].</p> Full article ">Figure 4
<p>(<b>a</b>) Bis-pyrenyl tweezers on a polyamide scaffold appropriate for aromatic guests. Redrawn from reference [<a href="#B49-surfaces-07-00049" class="html-bibr">49</a>]. (<b>b</b>) The UV-visible spectra of host–guest blend reveals a prominent absorption band at 526 nm, indicating charge transfer between them. The blue line is a pure diimide guest, the red line is a polymer-based host, and the black line is a host–guest blend. Reprinted with permission from reference [<a href="#B49-surfaces-07-00049" class="html-bibr">49</a>].</p> Full article ">Figure 5
<p>Structure of zinc porphyrin tweezers immobilized on TentaGel polymer (cross-linked polystyrene network with grafted polyethylene glycol units). Redrawn from reference [<a href="#B51-surfaces-07-00049" class="html-bibr">51</a>].</p> Full article ">Figure 6
<p>(<b>a</b>) U- and W-shape of PEG-bound molecular tweezers in acidic and neutral pH. Adapted with permission from reference [<a href="#B52-surfaces-07-00049" class="html-bibr">52</a>]. (<b>b</b>) Chemical structure of mitoxantrone which was used as the guest. The arrow shows decrease of fluorescence intensity. (<b>c</b>) Emission fluorescence of polymer based tweezers upon addition of mitoxantrone at neutral (left) and acidic pH (right). Reprinted with permission from reference [<a href="#B52-surfaces-07-00049" class="html-bibr">52</a>].</p> Full article ">Figure 7
<p>Water-soluble metal-bis-porphyrin end-capped with PEG. Adapted with permission from reference [<a href="#B56-surfaces-07-00049" class="html-bibr">56</a>].</p> Full article ">Figure 8
<p>(<b>a</b>) Structure of three different metalloporphyrin–peptoid conjugates (MPPCs) and (<b>b</b>) host–guest complex formation between MPPCs guests as follows: achiral host–chiral guest, chiral host–chiral guest, and chiral host–chiral guest. Adapted with permission from reference [<a href="#B58-surfaces-07-00049" class="html-bibr">58</a>].</p> Full article ">Figure 9
<p>Schematic proposed structure of the stimuli-responsive catalyst. Formation of hybrid metal nanomaterial, PAAgCHI/Fe<sub>3</sub>O<sub>4</sub>/Ag (L, H), where L and H refer to low and high levels of Ag nanoparticle loadings. The following color scheme defines the various components: red sphere (Fe<sub>3</sub>O<sub>4</sub>), gray sphere (Ag NPs), blue line (chitosan), and green line (grafted PAA; PAAg). Copied with permission from Ref. [<a href="#B65-surfaces-07-00049" class="html-bibr">65</a>].</p> Full article ">Figure 10
<p>Schematic illustration of the dual-function adsorption properties on surface-patterned flax with variable chitosan loading. The surface properties vary from a predominantly positive charge due to chitosan surface coating effects to a predominantly negative surface charge for pristine flax fiber (FFR; without the chitosan coating). The arrows in the lower panel highlight the incremental adsorption of RB (right to left), whereas MB increases from left to right. Copied with permission from ref. [<a href="#B77-surfaces-07-00049" class="html-bibr">77</a>].</p> Full article ">Scheme 1
<p>Schematic representation of three different molecular tweezers based on the type of the spacer, including (<b>a</b>) flexible, (<b>b</b>) rigid, and (<b>c</b>) stimuli-responsive tweezers activated by external triggers, such as light or other forms of stimulation denoted by the zig-zag line. Adapted with permission from reference [<a href="#B4-surfaces-07-00049" class="html-bibr">4</a>].</p> Full article ">Scheme 2
<p>The schematic arrangement of tweezers (red) and guest (green) parts to show the supramolecular polymers connected by noncovalent interactions.</p> Full article ">Scheme 3
<p>Schematic illustration of the stepwise synthesis process of SPS. Copied with permission from ref. [<a href="#B78-surfaces-07-00049" class="html-bibr">78</a>].</p> Full article ">